You might read on our thoracic outlet syndrome (TOS) forum sticky threads to see if some of your symptoms may fit, even if all don't , it can vary from case to case.
Often TOS or TOS like conditions , myofascial pain don't show on testing, until it is very severe.
The therapy suggestions may be helpful for many causes.

Just a few factors related to TOS , desk/repetitive work, sport injury/weight lifting, whiplash, forward head posture.

http://neurotalk.psychcentral.com/thread84.html
http://neurotalk.psychcentral.com/thread125577.html
http://neurotalk.psychcentral.com/thread135.html

Nerve irritation- could be from soft tissue impingement or scar tissue entrapment.