Dr D. doesn't have any ideas on the cause?
Has anyone mentioned scar tissue? Some people just seem to produce more or aggressive scar tissue than average.

Are the sx steadily increasing as time goes by. or has it been about the same level the whole time since the surgery?

I had pretty bad ulnar sx for awhile early on from my RSI injury, but it resolved with being off work, expert PT , and resolving the muscle spasms & trigger points..

I wonder if you can try treating the shoulder pain, and have a knowledgeable PT person manually check for trigger points and spasms..

Do you know what caused your TOS? Nerve, Vascular or disputed?
I’m guessing nerve as it usually has the more difficult recovery.
Unfortunately sometimes surgery doesn't help much..