Six Surprising Headache Triggers (WebMD):

1. Kicking back on the weekends. As tension dissipates, levels of stress hormones,such as cortisol and or adrenaline, decrease. This causes a rapid release of neurotransmitters,the nervous system’s chemical messengers. These send out impulses to blood vessels,making them constrict and then dilate, in addition to releasing other pain causing chemicals.

2. Self-treating your head pain. Taken too frequently (more than two or three times a week on a regular basis), the over-the-counter acetaminophen, ibuprofen, or naproxen you depend on to quell the throbbing may be hurting you instead of helping.

3. Female period. About 60 percent of all female migraine sufferers experience their migraines just before or at the start of their periods, according to the National Headache Foundation.

4. Harboring anger. Bottling up your feelings won’t do anyone—especially you—any favors. In fact, according to a study at Saint Louis University, this is the biggest emotional cause of headaches, even more so than depression or anxiety.

5. Food. Any of these contain chemicals that have the potential to trigger headaches: cheddar cheese (tryamine), chocolate (theobromine, phenylethylamine), diet soda (aspartame).