Rabbi:

Using a mouse can cause Carpal Tunnel Syndrome which can result in weakness and tendinitis anywhere on your arm, up to and including your neck.

I could not find a comfortable position for my arm while trying to sleep for years.

Finally the CTS became apparent and I had the release operation.

Soon after that all of the pains in my arm were gone completely and permanently.

There is an electronic test of the reaction of your nerves to a slight electrical shock that can diagnose or rule out CTS quickly and accurately.