Headaches will occur through a lot of reasons. Some people get it from stress, others from problems and over-thinking, while others get if for some medical reason such as lack of sleep or hereditary reasons. Migraines are the number one culprits of migraines and while you would want to address it fast, there will always be the pain killers and aspirin to help you out.
But recurring headaches should not be left to the pills alone. For serious ones, having a doctor or a neurologist check it out may be the best way to get to the bottom of it. You never know what you are overlooking to which only doctors can really figure out.