What causes migrains/headaches? i get a lot of them, and they do not find anything medically wrong with me, could it be stress related?

Generally Vascular: Migraines are generally considered vascular in nature meaning the blood vessles are expanded & cause the pain. Stress definitely can be a cause of migraines as can some foods, bright lights or any number of things. Once you have a migraine they are notoriusly difficult to stop so focus falls on prevention and if stress is causing your migraines, then stress reduction techniques will help.