What causes daily headaches (3-4 per day on the right side of the head?

See your doctor. Recurrent headaches like that are not normal. It could be any number of things: tmj, cluster headaches, migraine or tension headaches or something else. Your doctor will be able to help by better characterizing the pain (sharp vs. Dull, throbbing vs steady, length of headache, exacerbating factors, etc). Get it checked out.
Cluster headaches. See the image to your left. There are 3 main types of primary headaches. Tension headaches are bilateral non-pulsating. Migraines are unilateral and pulsating and associated with aura. Cluster headaches are associated with physical symptoms around the eye and multiple times daily.