I had/have thorasic outlet syndrome (TOS), but my symptoms vary from yours. My TOS improved dramatically with changes in posture. I stopped sleeping on my stomach, and I started sitting up straight in my chair.

Latest research shows that TOS is caused in susceptible people by the manubrium (bone) pressing against the subclavian artery. The subclavian artery feeds the thymus, the two carotid arteries and the two vertebral arteries. The lateral junctions to feed these items fall in different sequences in different people, so the symptoms from manubrium impingement are different from person to person.

The vertebral arteries run up both sides of the neck. They feed the thyroid gland(s), the ears, the visual cortex, the pituitary gland, and the hypothalamus (the brain's chemical lab). Autoimmunity represents a dysfunction of the hypothalamus-pituitary-thymus (HPT) axis, so you can see that reduced subclavian artery blood flow would seriously impact all of your complaints.

Unfortunately, even though I've seen improvements, I'm left with residual intracranial hypertension (IIH) headaches and vision impairment, because I hyper-inflated my eardrum during my TOS.

Thyroid deficiency can result from insufficient thyroid output autoimmunity (Hashimoto's) in some people. But thyroid deficiency can also result from cellular overuse of thyroid hormone. Hormone overuse comes from insulin resistance and metabolic syndrome. There is a minor chemical process loop outside of the main chemical Krebs cycle. In this loop tetramers of pyruvate kinase M2 (PKM2) catalyze substrate products of ATP phosphorylation into pyruvate for re-insertion into the Krebs cycle. This process can only be facilitated by the recombination of thyroid hormone .....from T1 into T2 or from T2 into T3.

Insulin is the hormone which transports blood glucose into cells. Insulin resistance means the blood fills with glucose and cells start starving. When the glucose gradient across the outer cell wall increases, PKM2 re-aggregates from tetramers into dimers, and loses its ability to recombine either pyruvate or thyroid hormone. This results in a loss of both cellular energy and thyroid hormone.

http://www.innerbody.com/anatomy/skeletal/upper-torso
http://www.fasebj.org/cgi/content/me...bstracts/474.4