Ergonomic Mice

I have shoulder pain and upper back with my mouse. It took five years. My physical therapy, I feel better, but when using the computer mouse, you experience muscle spasms and extreme stress on the shoulder. What should I buy for ergonomic device to relieve pressure on his shoulders, back and arms? I bought an adjustable armrest, but that was only in my chest the breastplate to be angry. I do not know if it's only in your home, your workplace or at home can be your workplace. If this happens to work, then you should talk to your supervisor and get someone to organize your workplace more comfortable for you. If not home, then you could go to stores that deal specifically with home offices and recommend what to buy. Try a mouse tray that attaches to the bottom of the table (or get a full keyboard tray with room for mouse, so can the mouse while the arm is held against his side and elbow bent 90 degrees, sometimes, if you make more use of characterization of the mouse can be useful to move the keyboard and mouse directly in front of your hand. You should never "reach" for the mouse .