Hi
There can be several causes for headaches like primary headaches which are not associated with any other diseases (example migraine, tension headaches and cluster headaches) or secondary headaches that are caused by some associated disease. Secondary headaches may be due to withdrawal from caffeine, high blood pressure, brain tumors, strokes, meningitis among other causes.
The exact diagnosis would depend on a detailed history with respect to the exact site, duration, time of the day, intensity, any associated symptoms like nausea, vomiting, visual loss, any neurological symptoms along with your past medical history.
You should consult a doctor for proper diagnosis if the headache is bothering you. Various tests such as blood tests, CT scan, MRI or lumbar puncture are usually necessary to establish a diagnosis.
Take care!
What sets off these headaches? Do lights or noises bring them on? At first read, it sounds like you might be suffering from migraines, which have turned into daily headaches.