A neurologist who is associated with a major hospital or University medical school program is most likely to be more familiar with TOS. This Dr should be able to dx. TOS, order whatever other tests are required to rule out other dx's, and perhaps refer you to a specialist. It might be useful to have a chest x-ray done beforehand, as this is almost always required - this allows the Drs. to see if there may be other problems such as an extra cervical rib, misshapen collar bone, large ribs, or other abnormalities present that show up on the film.

Thoracic or vascular surgeons also see TOS patients in the US, confirm dx and suggest treatment. These are the types of Drs who typically do surgery for TOS, there are some exceptions to this among hand surgeons and neurosurgeons I believe.

It sounds as though you may have some issues with blood flow when your arms are in provocative positions. I would be concerned as well. I think if it were me I would ask to see a vascular surgeon - perhaps two, to see if their opinions are the same. You may want to ask family or friends if they know of or have seen a Dr like this they would recommend (or not recommend, as the case may be).

With vascular TOS, if the damage being done due to compression of the vein and/or artery is significant, or the risk of a clot developing is fairly high, then surgery is often advised. Sometimes surgery can be avoided, but it is advised more frequently for vascular cases of TOS. The outcome is also generally better in these cases than for neurogenic TOS.

I'm not a Dr, just trying to help, please take what you can use and ignore the rest. (It's getting late, so if I made any glaring mistakes, please forgive me!)

beth