Thoracic Outlet Syndrome Support Group
Thoracic outlet syndrome (TOS) consists of a group of distinct disorders that affect the nerves in the brachial plexus (nerves that pass into the arms from the neck) and various nerves and blood vessels between the base of the neck and armpit.
If you've fixed your problem (I hope), congratulations. If you're still suffering from TOS without pain maybe you can do what I did.
I had TOS for 15 years before I discovered that I had it. I had seen neurologists in my hometown almost immediately after coming down with symptoms of TOS like weakness/soreness in my arms and hands, tingling/numbness in my fingertips.
Like you I had no pain.
I found out poor posture is strongly related to TOS. After reading about that I worked on my posture for a month. After a month a miracle (it seemed to me) occurred and I almost returned to 100% health.
Unfortunately, because of the jobs I had requiring duties that involved lifting heavy items, I had lapses.
After I retired I came close to 100% health again thanks to maintaining good posture and stretching. But I keep having relapses.
One thing that may have countered my periodic improvements was that I'd been sleeping on my affected right side for all the years (40) that I've had TOS. Neurologists warn against sleeping on your affected side or sides.
So if you haven't done so, check your posture. That's the first thing anybody should do who hasn't suffered a traumatic injury causing their TOS. Get on a stretching program. Don't sleep on the affected side. If both arms are afflicted try sleeping on your back.
Good luck. I hope after almost four years from your posting that you have fixed your problem and you don't need my advice.