Dear Coley6
If your therapist is right (and Im sure they are) , then the weakness in your serratus anterior is causing some lengthening of your trapezius muscles on your right side...the tension you are feeling is this muscle working hard to keep the shoulder blade elevated, it normally shouldnt work this hard...this lengthening is giving the illusion of a depressed shoulder...I dont want to say actual depression.
Ask your therapist what he/she thinks about taping? maybe relocating the shoulder blade and given some support to the serratus anterior will make it work more effeciently (given there are no neurological causes of course) and reduce the stress on the trapezius muscle...in the mean time massage is good in getting rid of some of that tension...
Best to do this with a skilled therapist- a good test...keep your arm in a position it is not likely to dislocate in (internally rotated, slight abduction elbow on the table palm facing down...ask someone to gently to lift your shoulder blade on the right up gently until its in the same position as the left, then let them hold it against your chest wall...if the tension in your neck eases off, then this is the problem.
Best of luck
Best of luck