What Causes Severe Joint And Muscle Pain?

I have bee having extreme joint and muscle pain for the last 100 days, I have been hospitalized once been in the emergency room twice , there have been some inaccurate diagnosis, No one seems to have any interest in helping me, prednisone helps this immensely, I have an appt. with a rheumatologist in a month, My research suggests I have poly myalgia rheumatica, My prednisone script expires in three days, No one seems to have any interest in helping me or diagnosing me, I did not know getting help is this difficult, I have health insurance.