I get headaches when lying down the longer i lie down the stronger the pain and then i feel so tired why is this happening?

See your doctor: To get the best answer to your question, you really need to be seen by a doctor for a full history, examination, and diagnostic testing. Please see your doctor asap about this.

Broad differential: The differential for headaches while lying flat is broad.. The cause can be innocuous such as from cervical spine disease or much more significant such as a dural avm. Please go see your neurologist to get a further evaluation. Take care.