Just an FYI.
My at one time very bad tendonitis and wrist pains completely went away.
At one point the pain extended to my lower back and across my shoulders, and you could feel the knots of muscles. When it got very bad I couldn't walk cool no more, and the pain in my wrists was very sharp.
Cause? Bad posture while sitting working at a computer for 10-12 hours a day and exercising hard on guitar. Having played solidly 1-3 hours a day from the age of 7 up to the age of 22 or so.
Solution?
2 sessions with a good osteopath got my back sorted to a point I could start recovery. It pointed out things about my posture I would not have noticed. I would suggest starting with your back regardless of where your pain is. Good posture transmits benefits across your body. And if you ignore it, like I did, it will spread to your back anyway.
I bought a $1000 ergonomic chair fitted to me. If I spend 50-60 hours a week on the thing, it better be good.
I have taken cod liver oil daily for over 5 years now. Don't like fish, but oily fish is meant to be good and really helped a mate of mine with arthritis.
I bought a zero-impact keyboard, its just a touch-sensitive thing. While things were bad, I swapped mice and other pointing devices from the left to the right hand regularly, but now I can use a normal mouse and keyboard fine.
Back stretches taught to me by an osteopath. I did these daily for years, but less often now.
Almost complete absence from
guitar playing for a while, and then working with the Jamie Andreas book and concentrating on better posture.
I think thats it. I'm no worse than anybody else now; sometimes I get a little sore here and there but my ability to recognise, compensate and self-cure is a lot better.