Back in 1992 I was undergoing physical therapy three times a week for spine/muscle issues and cervical traction was part of the treatment. I was suffering severe headaches following treatment but the physical therapist insisted I continue.
After one session I suffered severe scapular winging on the right side. During a Lidocaine epidural to release the muscle I experienced severe pain to the right clavical. Ever since I've had excruiciating pain, weakness, loss of ROM, hypertrophy and, subsequently, atrophy of the R sternocleidomastoid.
The pain/tension radiates across my shoulders, into my neck/jaw/head and down my back into the R scapula