Can daily migraines be a sign of something more serious? what?

It "can" be: It might indicate a brain tumor or other condition; however, it is far more likely that it indicates inadequately treated migraines. If your neurological exam is negative, then imaging is not always done, otherwise, it is often done once as a screen, then managed medically. See your dr or a neurologist for preventive and abortive medication assistance.

Need Consultation: Migraines are the brain telling you that you are not getting enough blood to feed the brain tissue. This can lead to strokes and other serious conditions. Have a neurologist and a dentist that is extremely good with treating TMJ do an evaluation on you.