Definitely talk with your doc. However, if he has been on Concerta for a while - the meds may not be the trigger. So do think about when the headaches occur. It could be the meds or allergies or even stress. And each one of those things requires a different response. How old is he?
If he suffers from frequent headaches, I would take him back to the doctor...he may not be able to use the concerta.