Repetitive sharp pain only on one side of the head is a symptom of a typical migraine. The pain during a migraine is very strong and might be accompanied with strange manifestations such as: strange lights, smells or confusing thoughts. These symptoms are called auras. The cause of migraines is not yet defined or clinically understood. You might want to try some over the counter non-steroidal anti-inflammatory drugs or analgesics in order to treat a migraine at home. Or you can visit a neurologist to exclude some other possible conditions that might be causing the symptoms; for example, a vascular disorder of the cranial blood vessels.