Does any one know about an ailment causing pressure build up in head and a possible cure?

My spouse is ailing for many years in spite of visiting several doctors. The problem is when the patient lies down to sleep there is a gradual (takes about 10 minutes) internal pressure build up that hurts in the head at the point of contact with the pillow. This compels the patient to shift the head to a different position. Once the head position is shifted the hurt and pressure is relieved for some time and after a while the pressure build up and the hurt starts at the new point of contact with the pillow. This cycle of pressure build up at continually changing points of contact with the pillow prevents the patient from naturally sleeping most portion of the night. This pressure build up is not present when the patient sits up and rests the head against a cushion or while standing. Obviously the patient cannot sleep in these positions. Several MRIs of the head & neck are taken. They have not revealed any abnormality. The frustrating thing is that none of the doctors including a few neurology specialists have not heard of such symptoms and as such have not been able to prescribe a cure. Some one prescribed sleeping tablets Clozopan which gives some sleep of 3-4 hours during night but causes the person to be uncomfortably drowsy through the day! Unfortunately, this medication has listed a whole lot of side effects that is causing anxiety about continuous use. Can some one please help with a medical name for this ailment and a possible cure even if it is an alternative medicine? Thank you very very much for a serious answer.