More on RSI here:
http://en.wikipedia.org/wiki/Repetit...#Warning_signs
I have had some carpal-like symptoms in the past from using the mouse. Playing games and doing work on the PC all day does it to me. I bought one of them mouspads with the gel wrist-rest thingy on it and it's awkward at first but prevents pain. It is worth noting though, gaming or things we enjoy doing with the mouse tend to cause symptoms like this alot LESS than monotnous work like repeatedly copoying/pasting stuff or dragging and re-organizing files and folders. Perhaps adrenaline plays a part in the work vs. play issue.