I get around 4 or 5 migraines a week and i can't pinpoint what causes them. preventative meds do not help. should i be concerned?

May not be migraines: These may not be migraine headaches. You might be getting tension type headaches, or you could be experiencing rebound headaches due to overuse of medication. Perhaps it could be coming from your neck. You need to be evaluated by a physician.

Cervicogenic HA: If you are getting ha (headaches) that often they are probably not true "migraines". The word "migraine" does not mean "severe ha". Migraines are specific CNS triggered symptoms. 85% of all bad has come out of the neck. You should get your head ct'ed just to make sure nothing is "upstairs", then look into your neck for the answers and for treatment.

Rebound: This sounds more like a transformed migraine. See a neurologist with experience treating patients with headache & consider her/his advice. Sometimes backing away from medications designed to treat headaches can allow for resetting to the original and typically more infrequent pattern.