Here's the deal bro. Go see an attourney NOW! The insurance company has a gaggle of lawyers advising them on ALL negotiations. You a lawyer? No? Then what chance do you think your ass has against a bunch of insurance company lawyers?
Let your attourney advise you on a good specialist. He/she will know some good ones. With a good attourney and a specialist that isn't in your companies pocket, you have a good chance at getting proper treatment.
Oh yeah, get ready to be photographed. There will be private agency investigators looking to catch you opening the mail box or a heavy door,etc with your bad arm. If your friendly with you neighbors tell them to expect a visit from some dickhead investigator asking questions about you.
Dude, this is for real and impacts your future. Use all available resources to your advantage. Be aware of what you do at all times. Live like your being filmed. All it takes is one mistake and your case is shot.
An attourney will work on contingency. It wont cost you a dime if you lose the case and they get 33% if you win.
Been there done that, got the surgery scars to prove it. Good luck.