Your symptoms could also be a version of Thoracic Outlet Syndrome (TOS) or RSI related.
Explore our TOS forum & sticky threads there to find out more info-
http://neurotalk.psychcentral.com/forum24.html
Any repetitive or sports injuries, previous whiplash, poor posture /head forward, etc..?
Do you have any neck or upper back pain, or tightness in the neck/shoulder muscles?