About a month ago I got my first E-Cig (penstyle) and ordered PG liquid to try. My E-cig and PG lic works great, love it! I then decided to get some VG liquid, for more vapor, but it seems every time I use the VG, I get a slight headache. I have noticed that if I mix the PG and VG together, my head doesn't hurt. Has this happened to anyone else or is it just me?? 