If you've even had some hits/falls, MVA..???
perhaps some expert chiropractic , just to make sure all is in alignment?

DC's can adjust any joint , not limited to spine.. but find a very skilled one that uses multiple modalities for best results..

How is your upper body posture?
If head /shoulders are forward of the body that can crowd the area even more.
Also the overly exaggerated extreme military attention posture.. can be as bad by compressing the other direction..

Did any of your PTs do trigger point work?
top rib mobilizations?
posture awareness work - like Alexander technique
did they push you forward thru pain?
or adjust to what you could tolerate before moving forward?

The best PT & self care for TOS is baby steps - no going forward until there is no pain increase that day or the next day..

Rushing this will only set you back, and working while trying to heal will not get you ahead of the game either..
I did not gain anything from PT until off work , the little help it gave me was negated by working..