Hi, Happy new years to you!
If you've tried lowering your nic level and still getting headaches you might be PG sensitive...it's not common but I've read of other people having reactions to PG....try and get a juice with a 10/90 pg/vg in a likeable flavor and vape on it for awhile...it's not going to give you the same throat hit you're fond of but it's worth a try. The Niquid link above is a really good place to get juice...they are not the cheapest but they are a high quality company and e-liquid, like many other things, can often be a "you get what you pay for" deal. You'll find that over time your vape preferences can change as well...when I first started I vaped 36 mg nicotine 70/30 pg/vg liquids because I smoked camel non filters for 18 years....now I am on 12mg 50/50 or higher vg content than that blends. Also, Alien Visions E-juice makes a tobacco flavor called "Boba's Bounty." It's been around for years, it's max vg, and out of all of the random tobacco blends I've tried that is one of only two tobaccos I still vape when I get in the mood. I don't know if you want another tobacco flavor, I know I am not really into them but that one has always been a popular favorite. I hope you find something that works for you.