I get them from time to time, and I think it has something to do with certain juices and or ingredients within them. I vaped Raspberry from my local shop for about 4 30 ml bottles worth, my daily vape, loved it. Started getting splitting headaches, ran out of that flavor, headaches went away. Still not associating the headaches with the flavor, picked up another bottle of it, BAM - Splitting headaches again, realizing it might be the juice, quit vaping it, headaches went away. I am really good friends with the guy that mixes for them, so I have him checking out the ingredients to see what it was. Maybe my head playin tricks on me, but it sure was pretty coincidental timing if it was. Hope you figure it out, I know it sucks.