Thanks Perna

Sunny, I don't think the arms on the chair have an effect, but it was that the chair had arms that made me think I would switch chairs. I could be completely coincidental.

No, a heavy chair fell on my leg when my leg. I was moving and carrying one end of it. I missed a step upt and went down. My leg was extended over that step when the chair fell onto my leg. I think it hyperextended my knee and tore things. Could hardly walk for weeks between knee pain and pain in the back of my calf and thigh. When I went to my doctor, he xrayed it and the xray was fine. He wanted to do an MRI but I have lousy insurance and I just don't have cash for an MRI, let alone to fix it.
I've noticed it still makes crunchy sounds, so I think something is loose in there and when it gets in a certain spot, it becomes painful and limits my movements. It always feels hyperended when I lay on my back.
But for about 6 weeks recently, I was limping badly and it hurt no matter what I did.

Sorry to go on and on.
For now, I can walk and it mostly feels good.
The chair may be simply a coincidence in timing, but I'm glad whatever worked.. did