InnerSelf.com

Approximately 90 percent of headaches are tension headaches. Tension headaches can be caused by almost any type of stress: too much or too little exertion, too much or too little excitement, too hot or too cold temperatures, too much or too little sleep, too erect or too limp posture, too much or too little food, and so on.

Migraine headaches are usually associated with nausea or vomiting and tend to be preceded by seeing flashes of light, zigzags, blind spots, or stars. Migraines are often triggered by psychological stress, but distinct from tension headaches, migraines tend to begin after a stressed person is finally able to relax; then that "relaxing" weekend or vacation becomes relaxation hell.