theres no surgery that can give you full range of motion, but there are some that can help increase it. Your biggest problem probably isnt ROM so much as it is stability. I would recommend doing rotator cuff stabilty exercises. Lat pull downs are a better option for you as opposed to pullups. I know you can do them and if theyre not hurting you i can see your frustration, I just personally wouldnt do it because of the instability and possible fatigue of your brachial plexus. You know your body best though so start light and gradually go up in weight until you reach a point that your comfortable, but struggle. If you need anymore help or have anymore questions dont hesitate to ask me or shoot me a pm!