Help!! Should I go to the ER?

I was involved in a car wreck back in August and suffered a torn rotator cuff. The doctor that I was seeing for it quit taking Medicaid (car insurance will not pay for it) and I was left without a doctor. My shoulder is swollen and it hurts, but I'm afraid to go to the ER because the last time I went, the doctor accused me of being a heroin addict and making up the pain just to get narcotic painkillers. I don't do drugs and I don't drink. Should I go back and tell them that I'm still hurting? What are the possible outcomes, should I decide to go? Any advice would be greatly appreciated.