I'm 68 and have rarely had headaches.  But recently I've had quite a few, often after exercise.  My doctor wants me to have a number of tests.  What could be causing this?
D000368:Aged; D006261:Headache / Q000175:diagnosis* / Q000209:etiology*; D006801:Humans; D005082:Physical Exertion / Q000502:physiology*