What Causes Pain In Posterior Part Of Head During Sleep?
Check blood pressure, cervicogenic headache.
Detailed Answer:
I read your question carefully and I understand your concern.
One cause of pain in that location could be high blood pressure which typically causes pain in the posterior part of the head. So if you haven't checked your blood pressure lately I suggest to have some measurement for the next few days.
Another common cause for pain in that location would be osteoarthritis of the neck spine which causes pain typically in the neck and the posterior part of the head. An x-ray would be a good simple initial exam for changes in the upper neck vertebrae.
Other possible cause might be tension type headache, a headache frequently related to stress and anxiety, which may predominate in the back of the head due to increased tension of neck and posterior scalp muscles.
Those are some of the most probable causes of such headaches. I remain at your disposal for other questions, but possibly including some more detail on when the symptoms begun, their frequency, other accompanying symptoms etc.