Most headaches are caused by the lack of oxygen going to the brain. Instead of taking a pain killer you must try this breathing technique first. Using a watch with a readable second hand, time your inhale time. It must be very slow and continuous. It should be about five or more seconds. Repeat this technique three times. Breathe normally for one minute and then repeat the entire sequence. After nine repetitions, your headache should be gone. If it doesn’t go away, breathe normally for five minutes and then repeat the nine repetitions again.