I still haven't been awarded my medical degree (going to medical school might help) but will tell an interesting headache story. My sister, a retired very smart lady with her MS in nursing and many years experience, once had the worst headache of her life. It wasn't the stabbing, intermittent kind that several of you have described, but a growing, horrible pain. Her husband said, "take an aspirin and lie down." Luckily she knew better and had him drive her to the ER. She insisted on a CAT scan, which revealed a cerebral aneurism! It was touch and go, and she had a new method called "coiling" (sp) which, after removing the leaked blood, repaired the aneurism, and she is alive and well today.
I have had two friends die of cerebral aneurisms. Each thought her horrible headache was normal and took an anti-inflammatory which just made the bleeding worse.
Sharon