Why as soon as i lay down too sleep my teeth start aching really badly wat can i do too stop this ?

Possible sinus : If your teeth are sound and your upper middle or back teeth hurt when you lie down The culprit may be sinus congestion. A few squirts of sinus de congestion may relieve the ache. If if your teeth are not sound, see a dentist to find the cause

Dental Exam: You'll need to be examined by a local dentist to determine why you are having these symptoms. By treating any problems you can stop the pain.

See a dentist ASAP: This is a sign of a tooth infection. A tooth pain won't go away without treatment and the infection may spread to your jaw, cheeks, sinus and to other areas of your head and neck. Visit a dentist ASAP for definitive diagnosis and treatment.

Please don't put off: evaluation. I would start with your dentist to determin if there is an infection or other cause of pain. Maxiallary sinuses are another source of pain.