My four year old son developed a fever and severe headache yesterday and it continues this morning. no other symptoms thus far. i have given advil and tylenol (acetaminophen) . do i take him to the pediatrician?

Yes: He needs to get checked out especially with "severe" headache with the fever. Even more concern with neck stiffness and confusion. It is most likely a virus, but you have listed a couple of symptoms that can go with meningitis. Either way, it's worth getting it evaluated unless he miraculously starts feeling better.

Fever and headache: Yes. Take him to the doctor if headache is severe. Especially if not improved with tylenol (acetaminophen).

Fever control : Please see the Emergency Department or Urgent Care right away. He may have signs of meningitis or encephalitis. Other causes an abscess, a mass or vascular problem.