Ever get an allergy test? I started getting headaches once in awhile last year. I found out I developed allergies after never having them. Started to take a 24hr Claritin, and they disappeared. Now I keep a box at work, home and in my case.
I eat super clean... no grains, legumes, or dairy for the past 5 years. Grass fed meat and vegetables is my main foods.
I have lyme disease that I got last year and I think the headache is related to that.