Why do i have major migraines when i try to fall asleep?

Hypnic migranes: There are a number of headache conditions that can be worsened during sleep. Specifically sleep is a quiescent state. Getting to sleep is a transitional state and sometimes this is limbo when migranes occur. Also if there is a primary sleep disorder, specifically apnea, oxygen levels may cause spasm of blood vessels making this more likely.

Many reasons: Possible causes: posture...Do not try to fall asleep reading or propped up on your hands. On your back also can cause this to happen. Try only on your side in a quiet dark room. Have nothing to eat or drink prior to bedtime except possibly warm milk (high in Amino Acid tryptophan). Sugary snacks late at night or even red wine also could cause this to happen. Also could try a hot shower on neck.