I've had constant migraines and headaches for 6 years and doctors don't know why but lately when I get a migraine I get realy bad chest pain too?

See a doctor. If you have chest pain along with a headache, especially if it's new, you should definitely get checked out. Do you have high blood pressure? What's your BP when you have these symptoms? You need a good physical exam, some blood tests, and an ecg. You may need a ct scan (head) and possibly one of the chest, if this is an arterial dissection. Stop smoking, if you do smoke. Update me!
After thought. If you have had unrelenting migraines , it may be worthwhile checking your heart for a pfo (patent for amen ovale) with a right to left shunt. There is some association between migraine and pfo and closing this with a catheter based procedure might help especially if you have had extensive other treatment. Please check with your doctor.
Heart or stomach ? It is important to rule out atherosclerotic heart disease. Tryptan class medications used to treat migraines can cause coronary vasospasm and chest pain especially in patients with coronary artery disease or prinzmetal angina. Also if you are using a lot of NSAID class drugs such as ibuprofen, it can cause gastritis or ulcers which can masquerade as chest pain. Please talk to your doctor soon.