Do you have a lot of arm or hand swelling?
That usually indicates more of a vein related compression.

My arterial pulse stops when my arms are elevated or pulled back to certain ROMs, but I don't seem to have any vein involvement. A percentage of the general population will have the blood flow stopped also at certain extreme range of motion {ROM} - but they would be non symptomatic of TOS.
I only had minor swelling during my worst time.

I managed to get beyond the worst of my symptoms without finding a "TOS" doc, my chiro & a couple of very good PT people worked out great for me.
-one thing my chiropractor told me was that clots are more likely to happen if the vein is involved and it's less of an issue for artery blood flow. I don't know if that is true or not though.

You may want to talk with a Vascular doc and get some more in depth knowledge about the vein/artery connection.
I thinks some had venous compressions most of the time at all arm positions - they were the very serious cases and some had clots and that was how they were dx's at the time.

Did you find our useful sticky threads {TOS drs & PT, & useful info} above our main TOS page thread list?
TOS main page -
http://neurotalk.psychcentral.com/forum24.html
tons of saved links, polls, important threads, videos, collected in those stickys - browse thru them as you have time.

PS
posture is a main issue to start working on - you are hurting and the next thing you know you are slouching or hunching to relieve the pain and it become s a bad cycle of worsening posture = more pain & problems.

Sharon Butler {book or website} has some great at home things that are very helpful.
we have posts & threads if you do a forum search on her name they will come up for you.