Happy you've found us, but sorry for the reasons why (if that makes any sense). I'm going to try to answer some of your questions, if I can. Keep in mind, I'm no doctor… and any so-called 'advice' you may glean from my post may be worth exactly what you've paid for it!
Your symptoms (sx) do sound to me like they could be coming from TOS. The fact that you describe them as "mild," to me, points more to them being more vascular (either arterial or venous) in nature (i.e., VTOS) than neurogenic (NTOS), than to being something that "could just go away on its own…," unfortunately. (I'm just talking about pain levels here, because of course, VTOS is every bit as serious a malady as is NTOS.)
I do think physical therapy (PT) sounds like a good idea. But you must be careful! It can be difficult to find a physical therapist who honestly knows how to treat (tx) TOS. Traditional, 'no pain, no gain' physical therapy not only does not work with TOSers, it can make you way worse! For example, no strengthening exercises should be introduced until certain upper body postural and respiratory dysfunction, muscle imbalances, etc. are addressed, and if something causes your pain levels to go up or other sx to flare, you should not do it, period. Try using the 'Search This Forum' function to pull up prior threads and posts on TOS modalities (like Botox injections into the scalene and pec minor muscles), the best type of PT, bodyworkers, chiropractic, etc.
That being said, I don't believe anything you were doing with your "bad" shoulder, in terms of exercises and stuff, was the cause of all of the sx you are having. Assuming you have TOS, you would be amazed at the number, variety and severity of sx which compression in the brachial plexus can cause in the human body! Your case may be like my own, in that it had what is referred to as an "insidious" onset. It happens. The thoracic outlet is a tight space, into which several cervical nerve roots, the first thoracic nerve root and the subclavian blood vessels compete for room to flow through, to the arm. Add in an anatomic anomaly or two, and you've got yourself a painful picture!
So, the focus you were placing on that shoulder may have triggered the other sx, but there had to have been trouble a'brewin' in there already; it was just a matter of time before hell broke loose…
Be thankful you do not have a lot of pain, that is a blessing! So many of your sx scream classic TOS: arms feeling heavy or weak, numbness and tingling in 4th & 5th fingers, loss of grip strength, fumbling/dropping stuff, color changes in palms (mine turn bright red, too!), high pulse rate, insomnia/trouble finding comfortable position laying down, etc., etc.
It is possible to have TOS bilaterally, for extra fun.
Depending upon what part of the country you live in, we may be able to help direct you to a vascular surgeon or other top TOS doc to get you diagnosed properly (doesn't mean you have to sign up for surgery right away!). They might want you to get some tests done, to confirm where the compression is, exactly. Also most likely to run a differential diagnosis, to rule out other pain syndromes TOS can closely mimic sometimes (like shoulder tendonitis, for example).
The good news is, if it is VTOS, you have a much better shot at a full recovery, as it is more of a simple mechanical problem than is NTOS. So many factors to consider, and every TOSer's case is different. There is still quite a bit of controversy in the medical world about TOS and how best to tx it… There is a ton of useful information captured in the sticky threads at the top of the main page of this forum, if you'd like to do some research.
Please keep posting here, to let us know how you're doing, OK? If you have any questions or concerns we'd be happy to help you if we can.
Take care,
Alison