Enlargement of head and headache! I don't think you can afford to ignore it. There are multiple causes ,some serious others just benign. One of these is Hydrocephalus
i..e increase in amount and pressure of fluid (CSF) in the cranium. First go to an eye specialist who will check your eyes to look for any evidence of increased intracranial pressure. You also need a CT scan
of head. You should consult a Neurologist
or Neurosurgeon in your town to get the right diagnosis and treatment.