Please Help -- Hurt Hand

It's finally right hand's all messed up from playing the

Specifically, from Mouret's Rondeau...It's the third bar here, -- go to the one for
the piano and click on "listen" to see the first page of the score. I
have pain now on the back of the hand, like half-way down between the
knuckles and the wrist where the middle and ring fingers have their
tendons or whatever those strings are called.

I was playing Mouret's Rondeau last night...and my right hand started
feeling more and more uncomfortable than it's ever felt, almost (though
not quite) an acute I stop. I was on a roll, but I'm getting
stupid-stitious in my old age, ever since I caught a herniated vertebra
and spraigned an ankle.

But this morning, I couldn't play that section of the Rondeau at all!!!

Even my wrist is involved!! Yes, the muscles are tight, but it's not a
cramp, since as soon as I stop it's gone, no more pain or discomfort.

I also do a lot of push-ups and (upright) bike-riding (will get a
recumbent soon) you think that has something to do with all this??
I also lift weights, etc.

Is there some kind of first-aid handbook for hands??