I have this too!!!! I did not understand why it was happening. The MRI scan of my neck was normal. I could not use my arms/wrists for few months (could not even lift a fork and had to use a plastic one). I suspected that it was carpal tunnel, although I didn't understand how it could have developed out of the blue, as I was not doing anything due to PCS/TBI. I am slowly gaining back the strength. I look forward to the day when I can play the guitar again.