Sue Dr for defamation of character?

My question is over the last few years I have had to go to my local hospital that has 11-12 full time PA's, DO's, or MD's and one of the DO's is the ER's Dept medical director. I have had to go to the ER on an average of 2-3 times a month over the last 4 years for verious reasons. But of my reasons out of 20 times I rarely ask for PAIN medicine. I've gotten pain medication maybe 1 out of 15 times. Each time its usually potassium or saline I get. I get potassium more than anything cause I have hypokalemia which causes my HR to go tachycardia. I also recently found out secondary adrenal problems, I've had BAD migrains, Ive had several cyst pop due do bad endometriosis (which caused me to have my uterus taken out last year at the age of 26), hypotension. Among other problems. Anyways, this one DO who is in charge has basically taken it upon himself to put into the computer system that Im not allowed pain meds from the hospital cause my trips there. But im not a "frequent flyer" is what my nurse friends tell me. Im not a drug seeker. I seek potassium more than anything. This DO has also called an old dr of mine and told him I was a hypochondriac. When actually I do have problems with me. So My question is when I got into a car wreck that wasnt my fault, guess who was in charge that night? HE WAS. he wouldnt give me medicine and I was in extreme pain. 2 other drs have told me HE (this DO) went in front of the board a while ago and made it impossible to get pain meds when I go to the ER now. But with my HX of having pain. 2 months ago I also had an attack where my HR got up to 189 and they refused to give me pain meds, which is what they usually would give cause the pain is soooo bad cause of PSVT. So Can I sue this Dr for Defamation of character? Or something else. He's always rude. None of his staff likes him, and for him to take my rights away when I get potassium way more than anything is crap. What are my rights???