[Ben Fury]

Were it my injury, I'd apply lymph drainage to the area and then work the shoulder through Sagittal, Axial, Coronal ROM VERY gently using AIS two second stretch at the end of each ROM with extremely low strain.

I can't help wondering if a muscle imbalance is a contributing factor. Your trapezius development is phenomenal, yet your anterior and lateral deltoid are quite typical looking. Is this usual in males in your family, or is this specific to the training regimen you've undertaken?

Early in my training career, I became overly fond of clean pulls and caused so much hypertrophy in my traps, that I started getting nerve impingement, leading to tingling in my hands and fingers. Deemphasizing traps for 6 months mostly returned them to normal, but I still have to avoid excess shoulder shrugging to prevent reoccurrences.