There are triggers that can cause headaches. They include:
bright lights
flashbulbs
high blood pressure
some cardiac meds
the odor of perfume
the odor of flowers
the odor of natural gas
the odor of cigars
hormone levels that fluctuate in your body
food additives such as MSG, smoked and processed meats
onions
vinegar (not white)
nuts, especially peanuts
pizza
avocado
picked and fermented foods
chicken lives
sour cream
doughnuts
fresh breads
herring
chocolate
yogurt
pods of beans
excessive tea
excessive coffee
excessive cola
excessive citrus fruits
excessive pork
excessive bananas
ripped cheese
certain alcoholic beverages
the TV
movies