Do you sit at a desk and keyboard for multiple hours? If yes, please recommend a good chair.

I've been working from home about 90% of the time since the pandemic lockdown era. I had a cheap office chair and had noticed my back starting to hurt after a few hours in it per day. I eventually wound up getting a Humanscale Freedom headrest chair, which has been awesome. These chairs are stupid expensive, but I bought mine used, and reeking of the previous owner's perfume. It took months for the smell to completely go away, but I saved about $1,000 over buying one new, and it is otherwise in mint condition.