Originally Posted by Daesin

Shrugging shoulders up gives you a false relief...let me explain.
With TOS there is compression of the nerve, artery and vein at the side of your neck. Shrugging up or forward will pull off some of the compression but it shifts muscles into really bad positions that have potential for long term damage. Tense muscles don't flow freely and therefore cause more pain. Your alignment gets all crooked.
You should aim for shoulder down and back....as if you are trying to put your shoulder blades in your back pockets and keep your chin level with the floor.
That is the goal posture for TOS.
It will be uncomfortable for a while and the muscles will scream at you because they have been in a bad position and liked it. It wont take long to get them used to being back in place. TOS is all about posture. with good posture you should see a reduction in pain.