Keyboard-Mouse & shoulder Muscles

I was suffering from a kind of shoulder pain for past few days. I thought this might be happening following stress the due to exercise. Even though i stayed away from exercise for couple of days the pain in shoulder did not cure. I cleaned up the mouse though i did not have much dust accumulated on the rollers to induct uneasiness in using it. I searched the net to get some tips about better arm, shoulder and wrist positions while using mouse and keyboard. I came across the following docs, hope this will be of some help for all of us.

Tips for Using a Computer Mouse

Posture Issues with Keyboard/Mouse Use