Root c/Crown pain....what could it be?

Yeah so I had a root c like 2-3 months ago, along with a crown on it. And up until about 3 days ago. My crown has been hurting A LOT like even if I tap it or something too cold is present. It also has a small thin lining which is where the c is at. Dunno if that has anything to do with it. So I went to the dentist like 2 days ago and they charged me $94.00 just to get xrays and "examine" to tell me that i will have to come talk to my root c doctor, so she gave me antibiotics and pain reliever and its not helping at all! I also have no insurance. Anyone else have this before? Oh and one more thing, I didn't know there were consequences to this root c thing, my doctor did not explain anything to me! Until now do I find out....I feel like suing but i don't know. I've got major toothaches and headaches, anyone please help or share experiences cuz I'm totally losing it.