It sounds very much like many scenarios we have read here.
If you can't locate a TOS doctor, please seek out some expert PT/ chiropractor/ body worker.. A good TOS knowledgeable dr would probably rx PT anyway, unless you are having clots or severe pain..
Poor/ineffective PT/DC/ etc is a waste of $$ & time and may even set you back, do not stay if you feel like there is no forward progress, esp if things become worse with treatment.
After a few poor PT experiences you will finally find a really good one..
Often a evaluation appt is a good way to get a feel for what they really know ask a lot of questions.
If you do a TOS crash course thru our useful sticky threads - it will help you know what to ask and you'll know if they are blowing smoke or really knowledgeable..
You may still need some top rib/alignment work to recover even more.
I was at an Ok stage but still probs with much activity, decided to try a PT teacher that had his own clinic. During the evaluation he asked if he could try dropping my top ribs and I said OK, it was simple and not painful at all. It worked !! amazingly

I had severe spasms previously and my chiro had helped a lot with resolving those but they had pulled my top ribs up and they got stuck like that..
It was why I had ongoing issues with minor use.
So next DC appt I told him what the PT guy had done , so then he checked my top ribs every time , they did pop back up a few times but he got them back down, then they finally stayed down and I could tell if they started to rise if I carried something heavy for awhile, as time past no problems anymore with that.