Greetings all, this is my first post in here. I'm a 24 year old male, with close to 4 years of barbell training. I mainly do a powerlifting oriented training, therefore I'm generally training with heavy weights (compared to my strength level of course). Although I'm constantly improving, every since I started I've always focus on form before weight. Before I get into my injury details, I apologize for the long post, however I'm looking for some advice since I haven't been able to get it properly from doctors. For the past 1 month, I haven't been able to train my upper body properly. During the last 2-3 months, occasionally I would get this stiffness on my right side of the neck (usually a couple of days after training overhead press while I'm doing common activities, usually driving, or working on my computer but not always) which would go away in 1-3 days by doing stretches. 1 month ago I got the same symptom (it happened after I drove). This time however, the stiffness didn't go away for 2 weeks. I kept training as usual, with a slight but unnoticeable strength loss on my upper body lifts. However, at the end of those two weeks, I finished an upper body day, and after the workout I felt I'd done something to the neck as I could feel it getting stiffer already. When I woke up the next day, I could barely turn my head and besides stiffness now I also had a sharp pain in my neck, behind scapula, and near my rear delt. For more than 1 week I couldn't even sleep, as laying down made my right arm go numb no matter what position I took. I kept stretching my neck (especially the levator scapuale) and after 2 weeks, my pain was gone, although the stiffness was there. During this time I didn't train my upper body as I couldn't lift as much as I wanted, so I stopped. This did not affect my squat and deadlifts, which I continued to do. After the pain was gone, I was looking at the mirror and I noticed my right arm wasn't looking right. That's when I found out that my rear delt wasn't contracting! (it remains semi-soft no matter the position) This was the reason I couldn't handle weights on upper body movements, especially pulling. So I visited a doctor, who examined the structure of the muscles in the arm with ultrasound. He found nothing whatsoever in the rotator cuff, labrum, or rear delt. Then he did the movement pattern and test, and said my range of motion and strength of rotator cuff is perfectly symmetric and then said that there is no shoulder impingment. He said that muscles in the neck could have pinched the nerve which could cause loss of motion (I didn't have full strength on my fingers and wrist initially, now it's almost there). He advised to keep stretching and wait 2-3 weeks. If the motion wasn't back, there was a test that you could do to see how much each the nerves are working/not working. Although every day it gets better, I feel it's taking way to long. I have no pain whatsoever, and I have full range of motion in my arm, besides the fact that I can't use my rear delt. My question is, if anyone had to deal with something like this, what should I do? Keep stretching and waiting? I've kept on doing squats and deadlifts as normal, and this week i did some very light unilateral upper body movements (to keep the blood flowing and improve muscle mind connection). I apologize for the long post again, but I tried to be as clear as possible. Thank you to anyone who managed to read the whole thing!