I really suggest stopping the gym work, it just aggravates the problem.. maybe in time you could go back to it, maybe not..
a good quick walking pace/treadmill can help to maintain fitness.

Did the PT or chiro , or MD even mention spasms, trigger points, top rib mobilization?
Any use of ultrasound, low level laser, Interferential ( IF) stimulation?

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

There are a few members from parts of CA.

If PT was doing the usual standard protocol, it will make TOS worse, we can't be rushed into aggressive stretches or weights.
If any trigger points - those must be resolved before anything else will help for the long term. Same for spasms no use forcing a muscle to stretch when it is already " freaking out" LOL

It all takes gentle baby steps to move forward, pushing thru WILL set you back..

I'm not sure about locations but these are in orange county CA posted by nospam member
http://andoaston.com/
http://www.niren-angle.com/
http://neurotalk.psychcentral.com/thread165979.html