There are many types of headaches with varying causes and symptoms.
Tension headaches, or chronic daily headaches, are characterized by muscle contractions that result in mild to moderate pain.
Mixed headache syndrome, also known as transformed headaches, are a combination of migraine and tension headaches.
Migraines are related to the constriction of blood vessels in the brain, as well as genetic abnormalities of the brain. Pain can range from moderate to severe, and can last from a few hours to a few days and usually occurs one to four times per month.