This needs to be examined by an orthopaedic surgeon
because different levels of the 2 shoulders can be due to SPINE PATHOLOGY ( like SCOLIOSIS
) which needs to be assessed clinically.
If there is Scoliosiss, then i advice u to take an x ray
of the spine ( AP & LAT ) to evaluate the degree.If
If there is no spine pathology , then this can be ignored if this is not causing any symptoms .Your pain is due to STRAIN OF ROTATOR CUFF
rather than due to different level of the shoulders.
Hope i have answered your question