Used to have serious wrist/arm pain. Used to spend a lot of keyboard time, but also used to exercise a lot.

Anecdotal, but what worked for me was stopping walking around with my hands in my pockets. Seriously! Must've been something to do with body tension - once I figured out that letting my arms swing freely when I walked places, instead of keeping them rigidly in my pockets, the pain went away and hasn't come back.