Throwing Shoulder

Rotator cuff tear 
http://orthoinfo.aaos.org/topic.cfm?topic=a00064
Shoulder labrum tear
http://orthopedics.about.com/od/shoulderelbow/a/labrum.htm
SLAP tear
http://www.orthoinfo.org/topic.cfm?topic=A00627

Those injuries are common with throwing athletes.

You should see an orthopedist (bone joint medical doctor). He/she should do physical tests and imaging tests.  This will determine what condition you have. Ultrasound can detect issues with your rotator cuffs, biceps tendons, etc. (mainly structures not blocked by bone). But if you need to see deeper into the shoulder such as the labrum, you need MR arthrogram. 

Consider prolotherapy. Some orthopedists do prolotherapy. See an orthopedist who does Dextrose (or other proliferant), Platelet Rich Plasma, and Stem Cell Therapy (aka prolotherapy)–a low intrusive, nonsurgical procedure involving injections of the proliferant dextrose etc., your platelets, and your stem cells. It will regenerate and heal the injury effectively and quickly. 

It’s best if the doctor uses ultrasound to guide the proper placement of the injections. Be sure the doctor administers multiple injections in the whole joint, not just one injection in a single location. The treatment should be thorough and comprehensive.