Seems like an injury to the long thoracic nerve -- you should seek out an experienced neurosurgeon to see what options are available.

Some folks to consider:

Susan Mackinnon
Washington University, St. Louis
http://nerve.wustl.edu/nd_transfers_...erve_disorders

Allan Belzberg
Johns Hopkins

Eric Zager
University of Pennsylvania

Robert Spinner
Mayo Clinic, Rochester

Hang in there and good luck!