Correction Appended Everything you thought you knew about migraine headaches — except that they are among the worst nonfatal afflictions of humankind — may be wrong. At least that’s what headache researchers now maintain. From long-maligned dietary triggers to the underlying cause of the headaches themselves, longstanding beliefs have been brought into question by recent studies. As if that were not enough dogma to overturn, there is growing evidence that almost all so-called sinus headaches are really migraines. No wonder then that the plethora of sinus remedies on the market and the endless prescriptions for antibiotics have yielded so little...