I have been getting headaches almost exclusively when I lie down, which is making sleeping difficult. It feels like intense pressure across my forehead (just above my eyebrows) and usually behind my eyes. When I lie on my back, it tends to move to the sides of my head. It occurs less than 5 minutes after I lie down, and if I sit up it is gone almost immediately. Occasionally I get similar headaches during the day, but they are transient and very mild.
I don't have problems with migraines, sinuses, teeth, or eyes. Ibuprofen, Flexeril, Vioxx, caffeine, haven't helped. My doctor has never heard of headaches primarily when lying down -- do you have any idea what this could be?