The shoulder blade, or scapula is one of the bones that is involved in forming the rather complex shoulder joint. The head of the humerus sits into the glenoid fossa of the scapula to help for the joint. The glenoid fossa is not nearly as large as the head of the humerus, so there is a "cuff" of muscle and tendon that surrounds the joint to help stabilize it. This is commonly referred to as the "rotator cuff". There are four muscles that make up the rotator cuff; the supraspinatus muscle, infraspinatus muscle, teres minor, and subscapularis. This rotator cuff can tear, and depending on the extent of the tear, approaches towards rehab can range from physical therapy to surgical repair. It is hard to tell you with any kind of certainty exactly what is going on with your shoulder without being able to examine you or take a history. For instance, it is possible that you could have torn your rotator cuff, but you also could have only strained a muscle which would be treated much differently. I recommend making an appointment with an orthopedic surgeon
to have your shoulder evaluated. They should be able to give you the best answer as to what is going on. I wish you all the best.