You might also want to consider working with a Feldenkrais practitioner to begin with. They help you learn to listen to your body and move naturally in ways that do not hurt you, such as when you were a kid. Very gentle and hands on, and should not flare you up but may help. If you have been dx'd with vascular TOS and are at possible risk of throwing a blood clot, I would be wary of any strengthening exercises at present, but maybe stick to stretching, nerve glides, ultra sound, massage (NOT deep tissue).

TOS-savvy PT's will start here, gradually build in some of the Edgelow exercises to open the chest, etc, based on your sx and tolerance. Beware PTs who advocate stretchy bands, hand bikes and weights - they usually make things much worse when sx are bad. Light hand weights do have a place, but much later in recovery once nerve sx have calmed down.

You can google Feldenkrais if it is not under our useful websites - it needs to be if it isn't! There are several in the Greater LA area if I remember correctly.
Alexander Technique classes and Tai Chi are also said to be very helpful, I haven't tried the first but just picked up a book of the method, and the beginning Tai Chi class I took still had way too many arm movements for me.
I probably would have continued anyway for the benefit I DID get, but the basket ball games on the other side of the thin wall kind of messed with the relaxation and "Zen" state of mind I hoped to attain.

Warm, not hot, baths with epsom salts to start and end the day are also said to be beneficial.

There are lots of good suggestions under the Useful websites link at the top of the main page. And keep asking questions, there's usually someone by to answer it before too long.

Best wishes,

beth