Shoulder pain after anti-nausea injection

Hi, about 7 weeks ago I had an anti-nausea shot for shoulder pain.  They gave it to me in my left shoulder. The pain at the time of the shot was intense!  I have had alot of innoculations in the military and nothing hurt like that.   A couple of days later I noticed pain and what I would call muscle cramping in that shoulder.  I would also wake up at night and feel my fingers tingling.  When I held that arm out to my side, part of the shoulder muscle was standing straight up!  It was rock solid.  the pain/cramping get's worse when putting my left hand on my right shoulder while keeping my left elbow close to my side.  When doin this and looking in the mirror, the middle of my shoulder actually looks concaved and I can feel the indention.  Anyways, it's been 7 weeks and I still have the problem.  It might be a little better.  It seems like when it get's super tight I can massage it to help.  What the heck did they do to my arm?  What's the problem I'm having?

thanks