Headache pain restricted to the right side of the head may be due to trauma to the right side of the head, various infections and some neurological diseases, according to American Family Physician. Frequent headaches that are localized to one side of the head are often classified as migraines, though they may also result from a condition known as cluster headaches.
There are a wide variety of potential causes of unilateral headaches, explains American Family Physician. These headaches are restricted to one side of the head or the other. Because of the many possible causes of a headache, it is critical for patients seeking treatment for a headache to provide as much additional information as possible when describing the symptoms and their recent history to their doctor to aid in diagnosis. While most headaches are not life-threatening, some unilateral headaches can be signs of severe trauma or disease, especially if this is the first time this kind of headache has occurred.
Migraine headaches can be debilitating and last for many hours, and while their specific causes are not fully understood as of 2015, some triggers include stress, poor sleep habits, monosodium glutamate, red wine, some odors and chocolate. In addition to right-side head pain, other symptoms include an aura or halo effect, flashing lights, a feeling of nausea and vomiting, explains WebMD.
Recurring headaches from cluster headaches and migraines are often restricted to one side of the head, states American Family Physician. However, migraines usually start on one side of the head and spread, while cluster headaches are exclusive to one side for their duration. Cluster headaches are more prevalent in men and often occur with additional symptoms such as sinus congestion and teary eyes that are restricted to the same side as the headache. While the cause remains unknown as of 2015, it is believed that an abnormality of the hypothalamus and the body's biological clock are involved, due to the cyclical nature of attacks, explains Mayo Clinic.