It would be important to try and have your son describe what is occurring to him, just to make sure that it is pain and not an abnormal sensation. If this is pain it could represent an intermittent paroxysmal hemicrania, meaning unilateral intermittent head pain. There is a headache type called "icepick" headache which results in severe bursts of stabbing pain. This would be unusual for a typical migraine. It would be reasonable to have an MRI of the brain. This would be unlikely for a seizure disorder, but I cannot exclude it completely. Lastly, disorders of the ear and related sinus should be excluded. A consultation with a pediatric neurology headache specialist would be reasonable. If you are in the area our expert is A David Rothner, MD. Good luck.
Here are references :
Weinberg JS et al. Headache and Chiari I malformation in the pediatric population. Pediatr Neurosurg.1998 Jul, 29:1
14-8
Kesler R. Headache in Chiari malformation: a distinct
clinical entity ? J Am Osteopath Assoc. 1999 Mar, 99:3,
153-6
Tubbs RS et al. Analysis of the posterior fossa in children with the Chiari O malformation. Pediatric Neurosurgery. 2001 May;48 (5): 1050-4
Blessings. Don't ever give up. Someone will have the answer.