I use both sewing and computer chairs at my machines.

I recently acquired a 24/7 chair at a charity auction, and loving it in my sewing room. I have gone to using my ironing board as a cutting board, because its higher and I dont' have to bend over as much.

A wooden chair. However, a friend has offered me what she calls an ergonomic chair, as she is moving house. All the better, all I have to do is pick it up. It may make a difference.

I use a straight back all wood. Works for me.

An old wooden desk chair, sturdy one, at my sewing table. No cushion. It works height-wise and lets me sew a little longer with my pinched lumbar nerve. When I am working at the kitchen table, quilting, I sit on a folding stool which gets me up high enough, slightly padded seat, no back.

I have a computer chair with wheels and a pillow I sit on.

My DH just bought me a new chair for sewing. It came from Staples. It is a manager style office chair and the model is called Lockridge. It has a lumbar support that really fits my back well.

Just use a dining chair.

a computer chair with wheels.

Ditto for me. Very comfortable and great support. I like having arms on the chair for those moments when I need to simply rest my shoulders/arms.

Good luck!