Don't get too gung ho on the stretches without talking to your Dr or PT.
PT for TOS is very specific. My PT does not want me to go into pain...just up to it. I have learned, and am reminded everyday that going past the line will kick you in the teeth. I swear sometimes the line moves!
Talk to the PT about TOS...they can run some physical movement tests to get a better idea if this is the issue.
Good Luck!