Hi, I can feel your situation.
Lot of confusion and lost hopes. Let me give my opinion.
The area you have marked can be 2 things : The supraspinatous muscle. Or the scapulothoracic articulation. The pathology lies in either of these.
Although physical consult and examination is always better, do a online consultation.
Next Steps
We may need to try intralesional injection therapy and specific exercise.
Only orthopedic surgeon can solve this unsolved mystery.
Health Tips
2 years is a big time for any pain to be present for.
To solve this chronic and neglected pain, we may need to go a step up than only medicines, depending on the pain/ weakness generator site.