So I was wondering if anyone here with lower back issues has found a chair that helped them sit?
Yes and no.
Sitting is the/my enemy. So, I use an adjustable standing desk with the best standing mat I could afford.
When I can/wan to sit, I sit, while the rest of the time I have the desk at my usual standing height and use the standing mat instead of the chair. The standing mat is key to help reduce fatigue & stress (feet, legs and back). I may also put it at different heights from time to time, depending how... tired my back is.
At least as important, I try to never sit longer than an hour.
I will get up and walk (either going out for a real long walk) or just be standing and walking in my home office. I may even dictate draft notes to a pocket recorder while I'm doing that.
As you can imagine, the chair is not the most important for me in that configuration but I do have one. It is one of those gaming chairs. Just a model for people that are well over my weight (so it's rather firm). It's ugly as hell (and quite large) but it offers all the adjustments I need : height and the ability to lean back as much as I wish (it can almost lay flat). I removed the arm rests that are rather... useless and cumbersome. When I sit, I also use a little cushiony stand thingy, on which I rest my feet at a slight angle. This seem to quite help my back too.
Imho, your doctor should be able to suggest you some better chairs than any random stranger online could... even if it's me ;)
Still, I hope this can help you a little bit: I know too well how our back can be a bitch.
