Office chair hurts my back. Is my employer required to buy me a chair that is comfortable and gives me proper support?

I do not think you have a cause of action here. You should file a complaint with HR that the chair hurts your back and you need a new chair and see where that gets you.

You can certainly ask your employer for a better chair

I agree with the other attorneys that posted here, tell HR that your chair hurts your back and that you want a better chair. There might be an action for workers' comp so I will change this question to w/c.

I agree. Ask HR for a better chair. The only way they would have to provide it under workers' comp law is if you file a WC claim and then the treating doctor writes a prescription for an ergo evaluation and then a new chair.

CA does support workers, but that does not mean your employer is obligated to buy you a new chair that is comfortable. If your old chair is worn out or does not function well, the company should provide a different chair. And if you have a doctor's note regarding a back issue, your employer may need to provide you with an accommodation. What is considered comfortable may be different to many people so keep that in mind.

I agree that you should first talk with HR about your non-supportive chair hurting your back. That may likely resolve the issue. I do not agree with most of what the other attorneys, who practice personal injury, have said in response to your question. If talking to HR does not resolve the issue, and sitting in a non-supportive chair has caused you pain to your back, then you can file a workers' compensation claim for that injury. At that point your employer has notice that your are disabled within the meaning of the ADA and FEHA which triggers their duty to meet with you in an interactive process to discuss in good faith if they can reasonably accommodate your disability without undue hardship. I doubt the Department of Fair Housing and Employment would feel that giving you an ergonomic chair is an undue hardship. If push comes to shove you may need to talk to a Workers' Comp attorney regarding the injury to your back and an Employment attorney regarding the possible ADA/FEHA violations. Good Luck to you!

Mr. Epperly and Mr Borah have advised you well. I agree with them.