I'm running into this problem over the last 12 months. Right shoulder sized up, tendonitis in the left elbow, swollen stiff fingers.

I have started with glucosamine, and mu GP is getting me xrays and mri for soft tissue

The biggest problem is psychological--its no longer a pleasure to pick up my guitar--even picking it up is painful...

There are plenty of cures offered in this thread---thanks to those who contributed.

I read that Jean Carignan, the quebec fiddle master, used to knit to keep his fingers supple, while he worked as a taxi driver.