Nearly 15% of people who make chiropractic visits do so because they suffer from migraines and chronic headaches. During a given year, 90% of people suffer from headaches. Only 1% of headaches seen in the ER have any serious underlying problem. Most reported headaches are caused by tension. Pain can range from mild throbbing pain to unrelenting agony. There are many different sources for headaches, some of which include: stress, overexposure to bright lights, fluctuation in blood sugar, and overexertion in exercise.