Attached is a simple one page exercise sheet to train the lower/mid trapezius (scapular retraction) and the serratus anterior. The assumption is that these exercises, along with other training and physiotherapy (ART etc), will position the shoulder blade in a better position. Ideally, avoiding forward tilt and a position that may be related to impingement.
Below is the pdf file:
thebodymechanic shoulder retraction basic
Adios,
Greg Lehman