Hi Dave,

Thought I would offer you a suggestion. It sounds more biomechanical based on your description so I am not sure it has to do with your thyroid.

My first thought based on your symptoms is that you might be describing TOS or Thoracic OUtlet syndrome. Your collarbone description kind of pointed me there. It could be that the nerves that come off your cervical spine and form into what is called the brachial plexus is being squeezed between your scalene muscle or the brachial plexus is getting compressed between the collar bone and the first rib.

I have TOS and got my from listing heavy objects. Usually TOS is accompanied by tingling in the pinky finger and next finger up. You did not mention that however. I never had that either so mine was atypical.

I would try to google some stretches for your sternocleidomastoid and scalene muscle and gently try to stretch them. You could also try the stretching with alternating heat and ice.

Does any particluar muscle feel spasmed? Do you feel any pain between your shoulder blades?

It does sound biomecahnical like soething is pinched or a muscle is in spasm and is pinching a nerve. That often happens and it becomes a vicious circle between the nerve and the muscle with the nerve getting pinched and overfiring and then the muscle spsming tighter to try to protect the nerve.

Could also be that the sternocleidomastoid muscle is spasmed and it putting pressure on C2 and C3. POr perhaps the subocciptal muscle is in spasm. I think both c2 and c3 innervate the neck which could account for your tingling there. Try to google c2 and c3 and some stetches for the subocciptal.

Hope this helsp. I'll check back later to see if you posted anything.