Could be pg or a flavoring or an additive.
I have many allergies. Do not assume anything. Just start eliminating. If it's pg, a few days or a week of pure vg will prove it. I am okay with pg, but the flavor additives reek havoc. That's why I diy most of what I vape, but if you don't want to do that, Virgin Vapor and Highbrow Vapor are extremely open with communicating- you can specify and they will not sell you what you don't want. Good luck, it's a pain, but it is worth it.
Try emailing JJ and see if they can help, first.