Headaches afflict almost everyone at some time or the other. Most headaches are functional, being caused by temporary upsets, and are not related to any organic changes in the brain.
They are often nature's warning that something is wrong somewhere in the body. The actual pain, however, arises from irritation to nerve endings in the shoulder, neck, and scalp muscles, and also in the smooth muscles encircling the blood vessels which serve these areas.
The common causes of headaches are allergy, emotional stress, eye strain, high blood pressure, a hangover, infection, low blood sugar, nutritional deficiency, tension, and the presence of poisons and toxins in the body. Allergies are often the unsuspected cause of headaches. The foods to which some people are allergic and which can trigger headaches are milk and milk products, chocolates, chicken, liver, alcohol, and strong cheese. Sneezing and diarrhea are further indications of an allergy