Not sure if you answer teeth questions but, i have a crown on my back left molar from a deep cavity. last night it was very painful when teeth touched?

Teeth problems: Working in ER's I have treated numerous tooth problems and it sounds like you have either in infection under your crown or that the tooth was drilled to deep and is sensitive. The best thing for you to do it take Ibuprofen 800mg three times daily and see your dentist ASAP. If you call the dentist he may call in an antibiotic for you as well. Good luck to you :)

See dentist: It may be that you have trouble underneath the crown you are unable to see. It is possible you may have an abscess/infection or pain from a remaining nerve root.

Yes, questions taken: Unfortunately, making a specific diagnosis over the internet without being able to see the tooth or a radiograph of it is not really possible. You may hace a cavity under the crown, a fracture, or a non-vital nerve. Please make an appointment with a local dentist for an evaluation.

Painful crown: A crown should not be painful. You need to see a dentist. Your tooth may be abscessed requiring a root canal, or there may be a localized infection in the gum tissue hat needs treatment. The only way to know what is going on is to see a dentist for an evaluation and then the proper treatment.