Has any doctor mentioned Thoracic Outlet Syndrome? Some nerves that supply the scapula area can become trapped in the area between the ribs and collar bone ([I]the thoracic outlet[/I]). This can happen in teenagers who carry heavy backpacks.
I know the pain you are talking about. Although mine wasn't TOS, I had a similar situation years ago. Intense chronic pain in my left scapula region, pins and needles sensation, muscle atrophy, etc. It took 3 years of non-stop doctors, tests and therapies. Fin***y diagnosed with a nerve entrapment in my neck. My anterior and medial scalenes were compressing a nerve that goes to muscles across top of shoulder and down into the scapula area.
Diagnosis was made by nerve conduction tests, EMG and a nerve block injection. I would suggest you see a Physical Rehabiltation doctor (Physiatrist) if you haven't already. They can be the great at solving a mystery. I was diagnosed by a neurosurgeon and the physiatrist did most of the testing to confirm. Ultimately I had surgery to decompress the [I]Dorsal Scapular Nerve[/I]. Woke from surgery pain free.
My injury/problem was the result of a car accident, but it can be caused by different types of strain on the neck - even carrying a heavy shoulder bag.
I read your post and thought I would throw in my two cents worth. I hope this gives you a new avenue to pursue. I remember the pain was relentless...
Best Wishes and Good Luck. Hope you find an answer & relief soon.