a few years ago, I lost a filling in one of my lower back teeth and part of the filling in an upper back tooth. I've been having bad headaches for well over a year, three weekends ago, it got so bad I couldn't take it anymore, since I have no insurance I went to the closest urgent care and paid $130 to be seen. The doctor/technician? Said fractured teeth were the cause. He didn't think I had an infection or abscessed tooth but gave me prescription for amoxicillin (just in case) and pain medication and find a dentist. I found a dentist who could see me in 4 days. Meanwhile, I took the antibiotics 450mg (ithink) twice a day and started feeling so much better within 24 hours and continued to feel better every day. The dentist took x-rays, told me the lower back tooth was badly abscessed/decayed and had to be removed, the other upper back tooth needed a root canal. They removed the lower tooth, left the upper until I can afford the root canal. It has been about three weeks since they removed the lower tooth and I am starting to get headaches again and I feel like I have an infection again or still? Is it possible to have an infection/abscess in another tooth that has a filling?

Yes, it is possible to have an abcess, which is an infection of the worse kind, in a tooth that is filled. Your root canal may have to be done sooner then you think. Why not just have it pulled and save the expense. Spending all of this money on repairs is senseless if you are not looking after your teeth with regular maintenance