I get headaches all the time. Some times I go a few days without one, but when I get it, it's here to stay for atleast a week at a time. The metal taste you say you have, are you sure your gums arent bleeding? because bleeding gums also taste like you have been sucking on a penny- not like I suck on pennies very often lol, but you know what I mean.
Next time you get this weird taste, spit it out and see if theres any color to it because for the last month or so, my gums have been so swollen, gone really soft and always bleed.