Dear Friend,
I would like to comment about your patient with shoulder pain. My humble advice is that please check for the dermatomal distribution. Check for the C4 and C5 nerve roots. Check the nerve tension , use neurodynamic principles , there may be a chance of compromise of the nerve in its course . It may be also due to the trapezitis.
Or the condition may be related to cacification of tendons of Bisceps and supraspinnatus (as you mentioned). Try some of the special tests with resistance . If so you have to make him do a lot of physical activities and also ex' s with pulley's in all directions.
This was my hypothesis of that condition and if you feel any difficulty in my discussion please ignore it. Thankyou ...