Its happened to me twice over the past year, the second happened earlier today between 10.30 and 11.30, the pain was terrible it was like my head was in a vice, throbbing pain all over my head, it was really unpleasant. I do not have any other symptoms related to this strange headache that has only occured twice for about an hour each time, but the pain is really intense and I wondered if anybody knew what could be causing it. I think it could be a migraine but I have no idea what is causing it.