I am using an istick 20 and nautilus mini at 8w. I am using 50/50 12 mg nic.
Hmmm... I know that iStick20 runs hot; is that the lowest setting it can do? Because 8w on that mod is more like 9 or 9.5w on any other mod, maybe even more. You didn't say what resistance you're using, but that can have an impact too; lower resistance generally means greater heat.
But I'd look seriously at the PG as a possible culprit; you may just be one of those not-rare unfortunates who are very sensitive to PG, perhaps intolerant. I personally have more trouble with VG, but after that burning effect I experienced at 90% PG, I don't discount the potential for sensitivity to PG. Maybe try some max-VG, which I think is about 80% VG, is that right, all you max-VG vapers? If you get any feeling of heaviness, tightness, congestion in your lungs with that, then you might have to back off the VG a little at a time until you find a comfort zone, but the chest problems from VG are somewhat less prevalent than the irritation from PG.
Andria
PS: I just noticed, you got here around the same time I did, you lurker you!

Welcome to the chatter, glad you stopped lurking, and sorry it had to be a major problem that coaxed you out of hiding!
