Though thoracic outlet syndrome is a possibility, it sounds much more like nerve compression of the C8 and possibly the C7.
Have you seen a spine specialist for this?
Have you had an EMG of your arms?
I suggest you see a Spine specialist as soon as possible. If you are already seeing one, then get a second opinion.
If you are using your primary doctor for treatment now, he/she is not qualified to diagnose and treat the problems that you are having.
Symptoms of C7 and C8 nerve compression.
C7
Patients who present with a C7 radiculopathy will show have neck pain, lower arm and along the medial border of the scapula. They may experience numbness and tingling into the middle finger. The Doctor may notice an absent triceps reflex. Weakness may also be noticed in the ability to straighten the elbow, and weakness in the triceps muscle, wrist flexors and finger extensors.
C8
Patients who have a c8 radiculopathy may present with neck pain, scapula pain, pain along the inner side of the arm, ring and little fingers. They may also have numbness and tingling in the ring and little fingers. Weakness may be noted in the finger flexors.
Fran