Headache is not a common symptom after a stroke. When it occurs, a few questions go through my mind. They include: 1) Could there have been bleeding at the location
of the stroke? 2) Could there have been swelling from the stroke that caused stretching and pain in the sensitive areas around the brain? 3) Could there have been a tear in one of the arteries which caused the stroke? 4) Could there be a clot in one of the veins of the brain? 5) Could the stroke have affected one of the headache centers, usually deep within the brain?
Sometimes, headaches can happen after a stroke regardless of whether or not one of the above occurred. I have seen patients develop chronic migraines as a result of an otherwise normal looking stroke.
It sounds like you should do two things. First, I would ask your physican to do a complete imaging work-up, including a detailed look at the brain, the arteries of the head and neck (not just with an ultrasound of the neck), and the veins of the brain. This can usually be accomplished by either a special MRI or a special CT (not the standard ones that most hospitals use in their routine stroke work-up). Second, I would ask your physician to start you on one of the many chronic headache medicines - including such options as topiramate, amitriptyline, or nortriptyline - all of which are good, inexpensive, headache medicine options.