I get headaches everyday what is the cause?

Many different poss. Could be blood pressure, could be hunger, stress, etc. Try to narrow down times and days. Take BP also when getting headache.
Needs investigation. This is a potentially very serious matter. You should see your doctor to investigate the cause. Often daily headaches are caused by over-use of analgesics (pain relievers) on a daily basis. The condition in that event is called rebound headaches. Nevertheless you should really make sure you don't have something serious like a brain tumor or uncontrolled hypertension.