You said the same kind of thing happened with different flavours, didn't you? If they weren't all creamy, for instance if some were tobaccos, as much as custards may be partly the culprit, there may be something else there. It could be PG, it could be VG and it could be the nic, sometimes people develop allergies/intolerances that they previously hadn't. Since we're not medical professionals (at least, I'm not), I think you do well in seeing your doctor. But what you possibly really need is to test your sensitivity to PG, VG and nicotine - I know it isn't that easy, normally they're only prepred to check other kinds of allergies. Although, I'm really not certain any of those can cause your throat to close like that, all I can remember is headaches, sore throat etc., but I'm not checking. Good luck, hope all will be ok.