Chronic migraines, which can be triggered by things such as hormonal changes, stress and certain foods, can result in head pain on one side of the head, explains Mayo Clinic. A hemicrania continua is another form of headache that produces pain on one side.
Doctors classify a headache as a hemicrania continua when a patient experiences a moderately painful, continuous headache that occasionally produces short, piercing pains for over three months, explains the National Institute of Neurological Disorders and Stroke. Over the three-month period, the headache must not shift sides or be interspersed with pain-free periods to receive the hemicrania continua classification. Although most individuals who suffer from hemicrania continua experience pain on only the left or right side of the head, a small percentage of sufferers experience pain on both sides.
Rarely, headaches that occur on a specific side of the head can be caused by a serious underlying condition of the brain, such as a tumor, infection, aneurysm or stroke, states InteliHealth. For this reason, it is important to report one-sided head pain to a medical professional. Other red flags that may signal a serious brain condition may include a headache that worsens over time, head pain that occurs along with a fever, and headaches accompanied by vision loss, passing out or difficulty with basic tasks, such as talking and speaking.