I've found out about my headaches (saved by a google seach again). One of the common explanations reads.
"When you exercise, or exert yourself physically, the muscles of the head, neck, and scalp need more blood to circulate. This causes the blood vessels to swell, which can lead to a condition called exertional headaches.
Headaches that most frequently occur due to exercise or over-exertion include jogger's headache and orgasmic headache (sex headache). While these may occur in isolation, they are most common in people who have an inherited susceptibility to migraine (one or both parents have migraines). THAT IS ME
It has been found that most exertional headaches WHILE PRETTY BLOODY PAINFUL are benign and respond to usual headache treatments."
I have been getting these headaches with "other" activities other than running so I think this is what I have.
So the cure is don't "over-exert" myself and desist from activities that cause these headaches or take an aspirin!
I'm off the the drug store/ chemist/ pharmacy.