There is a popular medical, pain management technique, called a ‘stellate ganglia block’, done with an injection of anesthesia into the upper thoracic and lower cervical area near the spine.
This seems to be a regular technique used for arm pain and maybe neck, head, and chest discomforts too. The stellate ganglia are part of the sympathetic nervous system and they come in pairs and lie on either side of the spine in the upper thoracic region. I often feel like something is stuck in there and years ago I used to actually tear the skin over the upper thoracic vertebrae in an attempt to relieve the discomfort I was feeling there. I am a lot more gentle and careful now. I did have someone do a drawing that illustrated my discomfort in this region and this is it. I felt pierced and wounded, as if by an arrow stuck in my upper back. I felt like I was carrying a weight on my shoulders.
Here’s a color drawing of the sympathetic nerve. The inferior cervical ganglia are also called the stellate ganglia maybe because they have so many branches reaching out in many directions affecting a large area of the upper body.
Stellate ganglia (inferior cervical ganglia)________________