PNo

Yes what you describe could be - similar to cervical signs it shows up as numbness and tingling in hands, weakness - especially with certain positions, cramping, swelling in the hands, a feeling of heaviness or the arms, pain, coldness, chest pain - under armpit, also some people can get headaches, vertigo, depending on which nerve is pinched in the outlet. A funny feeling in the neck at that area where the collar bone comes toward center of neck - almost like a pulsating. My veins in my hands got huge.

the doctor can check a few things, there is a test they can do to check your radial pulses that often get cut off as they do this maneuver with your arms. Mine are absent and really weak not only during the maneuver but also all the time. There are a couple other manuevers they use kind of to make a total picture, MRI is deceiving. the one way I got it more officially diagnosed was to get a scalene block in that groove in the front, they were able to narrow it down by a series of injections. Mine was a secondary condition after my ACDFs.

It is mostly treated by physical therapy, some people get it by a extra rib but that type is more rare and requires surgery. It would be more common for ACDF patients to get it from "splinting" (protecting the arm, holding tight awkward positions), a body alignment change after ACDF, and sleep position.

Mine flares up if I don't do the stretching and watch my positions.

I am surprised you can't find good info --read about Thoracic Outlet Syndrome and not the abbreviation TOS.