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What Office Chair Is Best for Lower Back Pain? (w/Examples) + FAQs

Most people spend more than one-third of their day sitting at a desk, yet about 80% of adults deal with lower back pain at some point in their lives. Your office chair is the single biggest factor that either helps or hurts your back during these long hours. A bad chair can make pain worse and cause new problems, while the right chair can reduce pain, improve your posture, and help you feel better by the end of the day.

What You’ll Learn

🪑 The core parts of your back and how sitting affects them — understand why your lower back hurts when you sit

💪 How to pick a chair that matches your body and your pain — find the features that actually matter for your spine

🛠️ Real office chair examples for different budgets and pain types — see which chairs work for specific lower back problems

✅ Common mistakes people make when buying chairs — avoid wasting money on chairs that don’t help

🎯 Actionable steps to set up your workspace the right way — learn how to use your chair so it actually protects your back

Understanding Your Lower Back and Why Sitting Hurts

Your lower back holds your entire upper body weight when you sit, which creates pressure on your discs and muscles. The five bones in your lower back (called vertebrae) have soft cushions between them called discs that absorb shock and movement. When you slouch or sit in a bad chair, these discs get squeezed, and your muscles have to work harder to hold you up, which causes pain.

A normal, healthy spine has a gentle curve in the lower back called the lumbar curve. This curve spreads your weight evenly across your discs and keeps pressure low. Sitting in a flat-backed chair or slouching removes this curve, putting all the pressure on a small area of your discs, which damages them over time and causes pain that gets worse.

Your body was designed to move around, not to sit still for eight hours. Every hour you sit without moving, your back muscles get tighter, your discs get more squeezed, and your pain increases. A good office chair supports this natural curve and lets you move a little, which keeps your discs healthy and your muscles from getting exhausted.

The Core Parts of a Back-Friendly Office Chair

Lumbar support is the most important feature for lower back pain. This is the part of the chair that pushes gently into the curve of your lower back to maintain your natural spine shape. Without real lumbar support, your discs flatten out and get damaged. Some chairs have built-in lumbar support, while others let you add a special pillow that you adjust up and down and in and out until it fits your curve perfectly.

Seat depth and width matter more than most people think. Your seat should be deep enough that you can sit back fully against the backrest with about two to three inches of space left between the front edge of the seat and the back of your knees. If the seat is too deep, you can’t use the backrest properly and you slouch forward, which kills your lumbar support. If it’s too shallow, your thighs don’t get supported and you slide forward off the seat.

Seat height controls whether your feet rest flat on the ground and your thighs are parallel to the floor. When your feet are flat and your thighs are level, your hip joints open up at a 90-degree angle, which takes pressure off your lower back. If your seat is too high, your feet dangle and pull your spine forward. If it’s too low, your thighs slope downward and create forward pressure on your discs.

Backrest angle and recline let you change positions throughout the day, which prevents your muscles from getting tired in one position. A good office chair backrest tilts slightly back (about 100 to 120 degrees from the seat) to match your natural spine curve. The ability to recline further lets you lean back during phone calls or thinking time, which rests your back muscles and reduces disc pressure.

Armrests reduce the load on your lower back by letting your arms rest at a comfortable height. When you type without armrests, your shoulders hunch forward, your upper back rounds, and your lower back twists to compensate, which increases pain. Adjustable armrests let you position them so your elbows sit at a 90-degree angle and your shoulders stay relaxed.

Material and cushioning affect how much pressure sits on your spine during long hours. Memory foam and high-density cushioning spread your weight across a larger area instead of concentrating it on one spot. Mesh material lets air flow through, which keeps you cool and prevents heat buildup that makes back pain worse. The cushioning should feel firm enough to support your weight without bottoming out, not soft and squishy like a couch.

Three Common Lower Back Pain Scenarios and How Chairs Help

ScenarioWhat Happens and How a Good Chair Helps
You sit at a desk 8+ hours per day and your lower back aches by 3 PMA chair with strong adjustable lumbar support maintains your spine curve all day, so your discs don’t flatten. Reclining ability lets you shift positions every hour, which rests tired muscles and prevents pain from building up throughout the day.
You have a diagnosed disc bulge or herniation and sitting makes sharp pain worseA chair that lets you adjust the lumbar support to your exact curve keeps pressure off the damaged disc. A tilt-lock feature lets you stay partially reclined, which opens up space between your vertebrae and relieves pressure on the bulging disc.
Your job requires constant sitting but you’re on a tight budget and can’t spend $1,000Budget chairs with basic lumbar support and adjustable height can work if you add an aftermarket lumbar pillow. Spending just $50 on a good lumbar pillow plus a $200 basic ergonomic chair beats wasting $600 on a fancy chair without proper lumbar adjustment.

How Different Types of Lower Back Pain Need Different Chair Features

Someone with general lower back stiffness needs a chair that encourages movement and lets them change positions often. A chair with good recline, a tilt mechanism, and basic lumbar support works well because shifting positions keeps muscles loose and discs from getting stuck in one shape.

Someone with a diagnosed disc bulge needs stronger, more specific lumbar support that they can adjust to their exact pain spot. Their chair should have a contoured lumbar system (not just a flat pillow) that they can move up and down and push out and in. A tilt-lock feature that holds them in a slightly reclined position takes pressure off the damaged disc and lets it heal.

Someone with sciatica (sharp pain running down the leg) needs a seat that doesn’t pinch their hip and a backrest that lets them lean back to reduce disc pressure. A wider seat, good cushioning, and the ability to recline help because they reduce the pressure that pinches the nerve.

Someone with muscle strain and tension needs a chair that supports good posture and prevents slouching. Armrests matter for this person because armrests keep their shoulders back and prevent their spine from twisting. A chair with moderate lumbar support and a naturally upright backrest position works best.

Real Office Chair Examples for Different Budgets and Needs

Premium Option: Herman Miller Aeron Chair ($1,395)

The Aeron has advanced lumbar support that adjusts in depth and height with precise knobs. The seat automatically angles slightly forward (called “anterior tilt”), which keeps your natural lumbar curve intact. It has a 12-year warranty, which shows Herman Miller stands behind the quality. This chair fits people with diagnosed back problems who sit 8+ hours daily and want to invest in long-term health.

Mid-Range Option: Steelcase Leap Chair ($1,089)

The Leap chair has a LiveBack technology that copies your spine’s natural curve as you move and recline. It adjusts to your exact body shape and weight, so the lumbar support stays perfect whether you’re sitting upright or leaning back. The tilt mechanism is smooth and easy to use, which encourages position changes throughout the day. This works well for people with moderate lower back pain who want science-backed support without the Herman Miller price tag.

Value Option: SIDIZ T50 Human Scale Chair ($550-$700)

The T50 has a waterfall seat edge that doesn’t cut off blood flow to your legs and causes your thighs to go numb. The lumbar support adjusts vertically and horizontally, so you get a customized fit. The mesh back keeps you cool during long work days. This chair works for remote workers and office workers who want quality ergonomic features at a lower price than premium brands.

Budget Option with Add-On: IKEA Järvfjället Chair ($260) + Lumbar Pillow ($40-60)

The Järvfjället chair has adjustable height, armrests, and tilt-lock, which gives you the basics. On its own, the lumbar support is weak, but you add a high-quality memory foam lumbar pillow that you position exactly where you need it. For under $320 total, you get a solid foundation that many people find reduces their back pain significantly. This works for students, freelancers, and people just starting to deal with back pain who don’t want to spend big money yet.

Specialized Option: Herman Miller Mirra 2 Chair ($895)

The Mirra 2 has PostureFit support that pushes into your lower back and pelvis to keep your natural curve. The seat is narrower and more sculpted than other chairs, which works really well for people with smaller frames or hip pain combined with back pain. This is a good middle ground between the ultra-premium Aeron and mid-range options, and it’s often a better fit for people under 5’8″ or with specific lower back curves.

Gaming/Extended Sitting Option: Secretlab Titan Evo ($499-$699)

The Titan Evo has 4D armrests that adjust in four directions, which reduces shoulder and neck strain that makes back pain worse. The backrest is tall and contoured, and the lumbar support adjusts in depth. Although designed for gamers, it works great for people who sit for 12+ hours and need maximum adjustment options. The reclining ability goes to almost flat, which lets your back fully rest during breaks.

Common Mistakes People Make When Buying Office Chairs

Buying a chair based on price alone instead of lumbar support. A $200 chair without proper lumbar support causes more back pain than a $100 cushion plus a $150 basic chair. Lumbar support directly impacts whether your discs get damaged, so it’s the one place where spending more money actually prevents expensive health problems later.

Choosing a chair that’s too soft and squishy. A plush, cushioned chair feels good for the first hour, but it doesn’t support your spine properly, and you sink into it as the day goes on. Firmness doesn’t equal discomfort — a firm chair with good lumbar support feels better by hour 8 than a soft chair that lets you slouch.

Ignoring seat depth and width for your body size. A chair that works perfectly for a 6’2″ person might be terrible for a 5’4″ person because the proportions are completely different. Always test a chair in person or check the exact measurements against your body, or you’ll end up with a chair that forces you into bad posture.

Not adjusting the lumbar support once the chair arrives. Many chairs come with lumbar support that’s set to a generic position, but your spine is unique. You need to adjust it up and down and push it out and in until it fits the exact curve of your lower back. Skipping this step means the expensive chair doesn’t actually help your pain.

Buying a chair but not fixing your desk height and monitor position. Even a perfect chair can’t help if your desk is too high or too low, or if your monitor is too far away and you lean forward. A good chair is only one part of a healthy workspace — you need the full setup to work.

Getting a chair with fixed armrests instead of adjustable ones. Fixed armrests force your shoulders into whatever position the chair designer decided, which might not match your body. Adjustable armrests let you position them so your shoulders stay relaxed and your lower back doesn’t twist to compensate.

How to Set Up Your Chair So It Actually Protects Your Back

Adjust the seat height first. Your feet should rest flat on the ground or a footrest, and your thighs should be parallel to the floor. Your hips should be at the same height or slightly higher than your knees. Measure from the floor to the back of your knee while wearing shoes, then set your seat height so your thighs are level.

Position the lumbar support to match your curve. Sit all the way back in the chair and find the curve in your lower back with your hand. Adjust the lumbar support pillow or built-in lumbar system so it pushes gently into that exact spot. It should feel like gentle support, not like something is digging into you — if it hurts, move it.

Set your armrest height so your elbows sit at 90 degrees. Your upper arms should hang straight down from your shoulders, and your forearms should be parallel to the floor when your hands rest on the keyboard. Armrests that are too high or too low force your shoulders to shrug or droop, which tightens your neck and upper back muscles and makes lower back pain worse.

Position your monitor at arm’s length away and at eye level. Your eyes should look straight ahead at the top third of your screen, not down or up. If you look down all day, you round your upper back, which shifts pressure to your lower back. If you look up, you arch your neck backward, which also twists your lower back.

Take movement breaks every 60 minutes. Standing up, walking around, and stretching for just five minutes resets your discs and muscles and prevents pain from building up. Set a timer on your phone if you need to remember, because sitting for more than two hours without moving always makes lower back pain worse.

Don’t slouch back into the chair expecting lumbar support to fix bad posture. Your lumbar support holds your spine in good position, but you still have to sit actively and keep your shoulders back. Slouching removes your lumbar support from doing its job, and you end up with all the pressure on your discs again.

Dos and Don’ts for Protecting Your Lower Back While Sitting

Do ThisWhy It Matters for Your Back
Choose a chair with adjustable lumbar supportYour spine is unique, and adjustable support lets you match it exactly to your curve, not a generic shape.
Test a chair in person before buying or get a 30-day return policyWhat feels good for 15 minutes might hurt after eight hours, so you need time to test it in real conditions.
Combine a basic chair with a quality lumbar pillow if budget is tightA $50 lumbar pillow plus a $200 chair often works better than a $600 chair with poor lumbar design.
Take movement breaks every hourStaying in one position all day tightens muscles and squeezes discs, but even five minutes of movement resets everything.
Adjust your full workspace (desk, monitor, armrests) not just your chairA perfect chair can’t fix a desk that’s too high or a monitor that forces you to lean forward.
Sit all the way back against the backrestThe lumbar support only works when you’re fully using the backrest, not when you’re perched on the front edge.
Use a tilt-lock feature to recline slightly during phone callsReclining to about 110 degrees takes pressure off your discs and rests your muscles while you talk.
Don’t Do ThisWhy It Damages Your Back
Buy based on looks or brand name aloneA chair that looks professional might have terrible lumbar support and cause more pain than a less fancy chair.
Use a chair with fixed lumbar support you can’t adjustGeneric lumbar support doesn’t match your exact spine curve, so it doesn’t actually help and might even hurt.
Slouch or “get comfortable” by rounding your spineSlouching removes your natural lumbar curve and puts all pressure on your discs, which causes pain and disc damage over time.
Keep your armrests fixed or too high/too lowWrong armrest height forces your shoulders up or down, which tightens muscles and makes your lower back twist.
Sit for more than two hours without standing or movingLong stretches of sitting without movement tighten muscles and squeeze discs, which builds up pain throughout the day.
Keep your monitor too far away or below eye levelLooking down makes you round your upper back, which shifts the load to your lower back and increases pain.
Buy a super soft, plush chair thinking it’s more comfortableSoft chairs don’t support your spine and let you sink into bad posture, so pain gets worse the longer you sit.
Chair TypeProsCons
Premium Ergonomic (Herman Miller, Steelcase)Precise lumbar adjustment, 10+ year warranties, research-backed design, adjusts to your body shapeVery expensive ($1,000+), overkill if you only sit 4-5 hours daily, takes time to adjust correctly
Mid-Range Ergonomic (Secretlab, SIDIZ)Good lumbar support, affordable than premium, still highly adjustable, quality constructionNot as customizable as premium, warranties shorter (5-7 years), still costs $500-700
Basic with Lumbar PillowVery affordable ($250-350 total), lumbar pillow is portable and works in any chair, good for starting outBasic chair alone doesn’t have all adjustment features, pillow can shift during the day, needs more manual setup
Gaming ChairsOften have tall backrests, good armrests, fun design, very reclinableMarketing hype over actual ergonomics, lumbar support often generic, usually heavy and hard to adjust precisely
Kneeling ChairsReduces lower back pressure by opening hip angle, good for people with disc issues, low costNot suitable for all-day sitting (causes knee pain), limits your ability to recline or take break positions, niche use
Standing Desk with StoolLets you alternate between standing and perching, movement throughout day, good for mixing positionsDoesn’t provide proper lumbar support when perching, causes leg fatigue, not ideal for 8+ hour days, expensive

Which Chair Type Works Best for Your Specific Problem

If you have general lower back stiffness and ache after sitting, you need a chair that encourages position changes. A mid-range ergonomic chair with smooth recline and tilt lock works best because you can shift your position every 30 minutes and prevent muscles from getting tired in one spot. A basic chair plus a lumbar pillow works if you commit to moving and adjusting frequently.

If you have a diagnosed disc bulge or herniation, you need strong lumbar support that you can adjust to your exact pain spot. A premium or mid-range ergonomic chair with adjustable lumbar depth and height is worth the money because it directly impacts whether your disc heals or gets worse. Budget options usually don’t give you enough adjustment precision for this situation.

If you have sciatica or shooting pain down your leg, you need a chair with a wide, well-cushioned seat and the ability to recline. Pressure on your hip or outer thigh from a narrow seat or hard edge pinches the nerve and makes sciatica worse. The cushioning and width matter more than fancy lumbar features in this case.

If you have muscle strain from poor posture, you need a chair that makes good posture easy and automatic. Look for a chair with slightly forward-tilting seat, armrests you can’t avoid using, and a backrest that naturally positions your shoulders back. This type of chair forces good posture without you having to think about it.

If you sit only 4-5 hours per day, you can get by with a basic ergonomic chair or even a decent gaming chair because you’re not in it long enough for bad support to cause real damage. Save your money and spend it on other health things like a good mattress or exercise.

If you sit 8+ hours every single day, investing in a good chair becomes preventive medicine that saves you from expensive physical therapy or surgery later. A premium chair that lasts 10+ years is cheaper per year than a $300 chair you replace every two years and deal with pain the whole time.

Setting Up Your Home Office Versus Your Work Office

At a home office, you control everything, so you can optimize your entire setup. Measure your desk height, adjust it if needed, position your monitor at exact eye level, and set up your chair with perfect lumbar support. You have time to make small adjustments and really dial in your setup.

At a work office, you often share furniture or can’t change your desk. In this case, focus on buying a chair that adjusts to fit your body regardless of your desk height. Bring a lumbar pillow with you if the company chair doesn’t have good lumbar support. A portable footrest helps if your desk is too high and your feet dangle.

If you work at multiple locations or travel a lot, a portable lumbar pillow matters more than finding the perfect chair. You can’t bring a $1,000 chair everywhere, but you can throw a $50 lumbar pillow in your bag and use it in any chair anywhere. Combine this with good posture habits, and you can manage your back pain even in less-than-perfect chairs.

How Your Weight and Body Size Change What Chair You Need

A person under 5’5″ or under 150 pounds needs a chair with a shallower seat depth and lower backrest height or they’ll drown in a full-size ergonomic chair. The lumbar support might sit at your mid-back instead of your lower back, and the armrests might be too wide. Look for chairs designed for smaller bodies or check exact measurements before buying.

A person 5’5″ to 6’0″ fits most standard office chairs, so you have the most options and the best prices. Most chairs are designed for this range, so you can shop from the widest selection. Focus on lumbar support adjustment rather than size since most chairs fit you properly.

A person over 6’0″ or over 250 pounds needs a chair with a deeper seat, taller backrest, and higher weight capacity. Standard office chairs might not support your weight properly, and the lumbar curve might be in the wrong place. Look for “big and tall” office chairs, which cost a bit more but are actually designed for your size instead of being a generic fit.

If you have a wider hip area, you need a wider seat but not necessarily a longer seat. A narrow, deep seat is worse than a wider, average-depth seat. Check the seat width measurements — most ergonomic chairs list this in the specs.

What to Look for in Product Reviews and Ratings

Real reviews from people who use the chair for months or years matter way more than five-star reviews from someone’s first week. Look for reviews that mention how the chair feels after eight hours of sitting, not just first impressions. Someone might love a chair for the first day but discover it causes back pain by week two.

Reviews from people with similar back problems as you are more useful than general reviews. If you have a disc bulge and someone with sciatica says a chair works great, that might not mean anything for your situation. Look for reviews from people who mention your exact problem.

Look for reviews that mention lumbar support adjustability specifically. A review saying “great lumbar support” doesn’t tell you if the lumbar support adjusts or if it’s just firm. You want reviews that explain whether the person with your body size could adjust the lumbar support to their exact spot.

Check reviews about long-term durability and warranty claims. A chair that feels great for six months but stops working by year two is a bad investment. Look for reviews mentioning whether the company actually honors its warranty and whether the chair still works well after years of use.

Discount reviews that focus only on appearance, brand, or status. A beautiful chair that matches your office decor but doesn’t support your back is a waste of money. Reviews from people who bought it because it looked nice aren’t relevant to your back pain problem.

When You Might Need More Than Just a Better Chair

If you’ve tried a good ergonomic chair for two weeks and your back pain hasn’t improved, you might have a specific medical problem that needs physical therapy or doctor attention. A chair can help once you’re on the path to healing, but it can’t fix a serious injury or condition by itself.

If your pain is sharp, shooting, or comes with numbness or tingling, talk to a doctor before buying an expensive chair. You might have a pinched nerve or disc damage that needs treatment first. Once you get that treated, then a good chair becomes part of your recovery.

If you sit in a good chair with proper setup but your pain gets worse, not better, after two weeks, something else is wrong. Your posture habits, your desk height, your monitor position, or something in your daily routine might be the real problem. A physical therapist can identify what’s actually causing your pain.

If you have a job that requires heavy lifting, bending, or repetitive motions, a good office chair only helps with the sitting parts of your day. You need to fix your lifting and movement habits during the non-sitting times or the chair won’t solve your problem.

How to Know if Your Current Chair Is Actually Bad for Your Back

Your pain gets worse as the day goes on, especially after sitting for more than three or four hours. If you feel fine in the morning and terrible by evening, your chair isn’t supporting you properly through a full work day. A good chair should feel about the same at hour eight as it does at hour two.

You can’t find a comfortable position no matter how much you adjust the chair. You shift around every few minutes looking for relief, but nothing feels right. This usually means the lumbar support doesn’t match your spine curve or the seat depth is wrong for your body size.

Your lower back pain goes away on weekends or vacation when you’re not sitting in that chair. If you sit in a different chair elsewhere and feel better, that’s proof your work chair is the problem. Compare the two chairs to figure out what’s different — usually it’s the lumbar support or seat depth.

You have pain in your legs, hips, or buttocks along with lower back pain. A chair with a narrow seat edge, wrong height, or poor cushioning pinches nerves and blood vessels, which causes pain in multiple areas. This means the whole chair setup needs to change, not just small adjustments.

Your neck and shoulders hurt along with your lower back. This usually means you’re rounding your upper back to compensate for bad lumbar support, or your armrests are forcing your shoulders into a bad position. Both problems come from the chair not supporting your spine properly.

The Real Cost of Ignoring Your Office Chair

Chronic lower back pain costs the US economy more than $100 billion per year in medical care, lost productivity, and missed work. Someone in constant pain misses more work, works slower, and has worse focus, which costs employers hundreds of thousands of dollars over a career. A $1,000 office chair that prevents this problem is incredibly cheap when you do the math.

People with chronic lower back pain miss work twice as often as people without pain, earn less money over their lifetime, and need more medical care. Ignoring your chair to save $300 today costs you tens of thousands in lost earnings and health problems later. A good chair is an investment in your future earning power and health.

If your lower back pain gets bad enough, you might need surgery, which costs $50,000 to $150,000 and doesn’t always work. Many people end up with chronic pain even after surgery. Spending $500 to $1,000 on a good chair is preventive medicine that keeps you out of surgery.

If you develop chronic pain, you might not be able to do your current job or any job that requires sitting. This changes your entire career path and earning potential. A good chair is one of the easiest ways to protect your ability to work in your field.

FAQs

Can an office chair really fix lower back pain, or is it just one part of the solution?

No, a chair alone doesn’t fix pain. A good chair prevents pain from getting worse and creates conditions for healing, but you also need proper desk setup, movement breaks, posture habits, and sometimes physical therapy or medical treatment for actual healing.

How much should I spend on an office chair for lower back pain?

Start at $300-500 for a solid mid-range chair with good lumbar support. If your budget is lower, spend $150-200 on a basic chair and $50-60 on a quality lumbar pillow instead.

Is lumbar support that adjusts in and out better than lumbar support that only adjusts up and down?

Yes, adjustable depth (in and out) matters more than height alone. Your lumbar curve depth is unique to you, and depth adjustment lets you match it precisely instead of forcing a generic shape.

Can I use a regular office chair with just a lumbar pillow instead of buying an ergonomic chair?

Maybe. If the chair already has decent height adjustment, seat depth, and armrests, adding a lumbar pillow works well. If the chair is bad in other ways, a pillow alone won’t fix it.

How often should I replace my office chair?

Every 7-10 years for quality chairs (Herman Miller, Steelcase), or 3-5 years for budget chairs. If the lumbar support flattens out, armrests break, or the tilt mechanism fails, replace it immediately.

What’s the difference between a “gaming chair” and an “ergonomic chair” for back pain?

Gaming chairs are designed to look cool and recline far back; they rarely have precise lumbar adjustment. Ergonomic chairs are designed around actual spine health with customizable lumbar support. Ergonomic chairs work better for back pain.

Does chair brand name actually matter, or can I get a cheap chair that works?

Brand matters somewhat because expensive brands use better materials and have longer warranties. But a mid-range brand with good features beats a budget brand, and a cheap chair plus a good lumbar pillow beats an expensive chair with bad lumbar design.

Should I buy a chair online or test it in person first?

Test in person if possible because what feels good for 15 minutes might hurt after eight hours. If you buy online, get a 30-day return policy so you can test it in real conditions and send it back if it doesn’t work.

Can I adjust my way out of a bad chair, or do I need to replace it?

You can only adjust so much. If the seat is too deep or the backrest angle is wrong for your body, no amount of adjustment fixes it. If the lumbar support is too soft or in the wrong spot, adjustment won’t help either.

What should I do if a good chair still causes back pain after a week?

Check your full setup first — desk height, monitor position, armrest height, and posture habits. If everything else is right and the chair still causes pain, you might have a medical issue that needs a doctor, or the chair proportions don’t match your body size.

Is a more expensive chair always better for lower back pain?

Not always. A $1,000 chair that doesn’t adjust lumbar support properly is worse than a $400 chair with excellent lumbar adjustment for your body. Price matters less than whether the features match your specific needs and spine curve.

Can I use a standing desk instead of an office chair to avoid back pain?

No, standing all day causes different problems (leg pain, foot pain, lower back pain). The best approach alternates between sitting in a good chair and standing for breaks, not replacing one with the other.

What’s the best office chair for someone who’s very tall or very short?

For tall people, look for chairs with taller backrests and deeper seat depth (Herman Miller Aeron, Steelcase Leap). For short people, look for chairs with shallower seats and lower backrest height (Herman Miller Mirra, brands that make “petite” sizes).

Do I need a special “medical” or “orthopedic” office chair?

Medical chairs aren’t necessary; a good ergonomic chair with adjustable lumbar support does the same thing. Avoid “orthopedic” labels because they’re marketing terms without specific standards or requirements.