Pinched nerve in shoulder,neck and armpit .had this before,took an mri picture,no herniated disks!! can muscles cause this? what is the treatment?

Different causes: Pain radiating down the neck to the shoulders levels, is very often generated by the cervical facets, usually the last 3- C4-5, C5-6 C6-7. A compressed nerve root gives you a radiculopathy down the arm but thecause of compression may be a herniated disc,a neuroforaminal stenosis or a hypertrophied cervical facet that narrows the neuroforamina, or it can be compressed anywhere else down the path