You can't lie down because it hurts. You can't chew because it hurts. The dentist or the assistant will ask you those questions to determine what type of emergency treatment will be required. When you arrive at the dentist's office, he or she will do an oral examination to see which tooth is bothering you and then diagnose the source of the pain. Your dentist may also want to take x-rays to help in the diagnosis.
Treatment can then begin to alleviate the pain and address the problem.
Low cost or free dental clinics are available in most communities. They may not be accessible 24 hours a day. Unfortunately, some people are unable to afford immediate dental care and do not have access to 24 hour dental care. In these situations the only alternative is go to a hospital emergency room. You will receive an medical evaluation and treatment without having to pay first.