Need Help Correcting an Imbalance

Hi guys. Ive created a problem in my neck/upper back in which somewhere in my neck/traps will lock up for a few days after any training in which my arms are over my head, the the pain/tightness is localized to the left side of my neck/traps. last year I had a grade 2 a/c joint tear from skiboarding, my right subscap/lat is usually very tight but I can occasionally loosen it up with some tennis ball action. but it always comes back.

I also used to do alot of shrugs, very heavy, with little to no warmup. I kept pushing through the pain through several months. after joining this forum I learned alot of things, but i still can’t figure out how to address this problem. I’ve seen an ART practitioner with some sucess, but he doesnt seem to know or want to tell me how to correct this problem. thanks guys.