You might want to ask your doctor about cluster headaches. They are quite painful, my husband says it feels like someone is taking a sledge hammer to his head at times, they wake him up from a dead sleep and affect his entire day. The headaches tend to last for weeks sometimes a month at a time and he gets very little releif from them until they have run their course.
He went through cat scans, dentists, neurologists before he was diagnosed. One of the characteristics of them is a post nasal drip after the headache has peaked. Good luck