Repetitive strain injury (rsi) solution number 4: After my unsuccessful try #3 I exchanged my usual mouse against a trackball-mouse.
Actually a trackball is an inverted mouse. So there you move the "mouse-ball" directly and the "mouse-body" stands still.
This is a good solution - it's a complte other way to operate your mouse cursor. But imaging - after a couple of weeks - you're still operating the same way all day long. You just re-schedule your RSI problem. Think about it.
At the end I had to say this can not heal a Repetitive Strain Injury for a very long time. Then I remembered my doctor who detected my problem in the upper back. So I tried sitting stright up on a funny sitting ball. So this was my Repetitive Strain Injury solution #5.