TriCare prior authorization

My physician is refusing to fill out the prior authorization paperwork so that my insurance will cover the medication. I'm so angry about it because I qualify for it to be covered if they would just complete the paperwork. It makes me wonder how they can even get away with doing this. She is definitely not working towards my best interests. The reason I was given was because she has gotten so many requests for prior- authorizations that it's too much work for her. Does anyone have a suggestion for a work around? My insurance is Tri-Care