Migraine and cluster headaches commonly focus only on one side of the head, explains Harvard Health Publications. A typical migraine headache causes severe, pulsating, throbbing pain that frequently starts around the temple and eye on one side and then spreads to the back of the head.
Cluster headaches are uncommon, but when they occur, they always produce very severe pain on one side of the head. The eye becomes watery and red; the eyelid may droop on the side of the head experiencing pain; and the nose runs or becomes congested, explains Harvard Health Publications. Cluster headaches start without warning and usually last for 30 minutes to an hour from one to eight times each day. Migraine and cluster headaches occur less often than the common tension headache, during which individuals feel a dull, pressuring pain on both sides of the head.