If you've got neck and shoulder pain from sitting at your computer all day, here's a suggestion that can bring you some relief. Switch your mouse to your left hand.
The Occupational Health and Safety Research Institute of Montreal asked hundreds of right-handed volunteers to control their mouse with their left hand for one month.After the month was up, the volunteers found they made much smaller movements with their shoulders, arms and wrists when controlling the mouse with their non-dominant hand. And it's these movements that lead to neck and upper back problems.
So why did swapping hands make a difference. Well, visualize your keyboard. The letters are to the left and the number keys are to the right. So the keys you use the most, the letters, are never centered in front of you. Then, when you click the mouse with your right hand, you have to stretch your arm out further to get the job done.
So having the mouse on the left side actually balances your movements. You shoulders are more square and you don't have to reach out as far. Give it a try and see if you notice a difference.