Scott,

Sorry to hear about your issues. I am both a drummer and a keyboard player and my hands, wrists, and back take a beating. It's really all tendonitis. The #1 reason for hand and wrist pain is; Poor technique and bad ergonomics. Believe it or not.

I had a piano teacher examine my technique and found flaws which I have worked on and now find that I can play for hours pain free. With drumming, it was mostly ergonomics with a little technique thrown in for good measure. I realigned my setup and started playing correctly and the pain went away.

You will have to rest your tendons for a while until they heal and then start working on your technique.

Best of luck and feel better soon!