I had this problem too a few years ago. The main thing that happened to me was that I used to wake up with numbness in my wrists. The steps I took which helped were to get a vertically oriented keyboard and mouse. I currently use these and the problem has not recurred in over two years:

http://safetype.com/

http://www.evoluent.com/

Although I do recommend you exercise more and have a more thorough evaluation by a doctor, as others are recommending.