if it is in your mouse hand i would be willing to bet that you press harder than you think while scrolling. i know i've been guilty of the same. the pressure on the nerves does minor damage over time, but unless it is a chronic pain i wouldn't worry too much. it sounds stupid and they look goofy, but one of those oversized gel-filled handwrests in front of your mouse may just be what the doctor ordered.
if that fails - do as the feline female ordered, wank with the other hand.
