Tendonitis, maybe. I had pain in both wrists simultaneously, and was diagnosed with both carpal tunnel and tendonitis.

If your wrist is swollen, put some ice on it, and pop an Advil (or was it Tylenol) ... a medication that reduces swelling.

Here's a good article with suggestions:

http://orthopedics.about.com/cs/hand...tendonitis.htm

http://www.itendonitis.com/ specifically this section: http://www.itendonitis.com/treatment.html