Sex headaches are often more common in males, middle-aged people, and in people with other headache disorders such as migraines, exertional headache, or tension headaches.Primary sex headaches are sex headaches that do not have another underlying cause. The reason someone has primary sex headaches is not known. Some researchers believe that primary sex headaches are from excessive contraction of neck and jaw muscles during sexual activity. Others believe primary sex headaches may be from changes in blood flow to the brain during sexual activity.