hi Headache immediately following a head injury usually clears after minutes or days but sometimes headaches may persist for months or rarely years. The long-term headaches are called post-traumatic or post-concussion headaches. One can understand why headaches may follow a moderate or severe injury to the brain such as a concussion (bruise) or laceration (tear). What has been more difficult to understand and has presented an ongoing controversy are chronic headaches following mild head injuries. Mild injuries of the brain are characterized as a concussion (a brief disturbance of brain function causing loss of consciousness or transient difficulty in thought processes). Because the neurological examination after mild head injury is normal and standard tests as well as imaging studies (such as MRI or CT of the head) similarly fail to reveal abnormalities, many thought that the symptoms following mild head injury were psychological. thanks for your query...