Curious as to the referral to a neurosurgeon. I guess they're concerned about a plexus injury because of the loss of sensation? I would guess an orthopedic surgical consult is in order to determine if repair is needed or if they'd like to pursue conservative treatment first. I'd probably expect a PT referral either way.
The partial tear and bursitis makes 100% sense to me with the symptoms you have. I've had a recurrent case of bursitis acting up on me the past few days, and it can hurt like a son-of-somethin. Add to that a partial tear, and movement can become very painful if not impossible.
A bursa is a fluid filled sack that helps seperate tissues and lets them move across each other. Most people have a bursa located under the deltoid muscle and the acromion. Other bursas can be located at the hip or under the shoulder blade. Bursitis can be treated conservatively in PT or the Physician may want to inject it. They can be lingering and bothersome, but I've had good success with bursal massage and alternating isometrics muscle contraction with and without steroid injection. The bad thing about the subacromial/subdeltoid bursa is that, because of its location, if it becomes inflammed, it can really cramp up the structures located in the shoulder. There isn't much room under the roof of the shoulder (acromion) with rotator cuff tendons passing through as well as the bursa. You'll definately want to get it happy again, so that the rotator cuff has the room it needs to heal up.
Your rotator cuff consists of four muscles that move and stabilize the arm on the shoulder blade. Three of these muscles bring the arm into external rotation (the wind-up of a pitch: supraspinatus, infraspinatus, and teres minor) and one brings the arm into internal rotation (the actual pitch: subscapularis). From my experience, the supraspinatus is the most injured tendon. The meat of the muscle is located just above the spine of the shoulder blade (a ridge that runs across the shoulder blade form the inside lower corner to the top outside corner). Like the bursitis, the rotator cuff injury can be treated conservatively with modalities to decrease inflamation followed by progressive strengthening of the rotator cuff, or it may require a surgical approach. Your MD will make that recommendation to you. Either way, follow your MD's orders closely (so you don't mess up a repair or worsen the tear) and work hard with your PT.
All things considered, these are pretty common injuries and should rehab very well. I know that it sucks being down for a while, and the pain is nothing to sneeze at, but the good news is that this is usually nothing that should keep you out for too long. Thanks for the update, and I hope sincerely that you are feeling better. Keep us informed as to what the docs say.
--nathan