PG tends to give a harsher feel to the the throat, especially when you're first starting out. Mixes using 24mg nic or more usually have higher ratios of PG (I know there has to be a scientific reason to this but all I know is it's impossible to find a 30/36mg liquid that is pure VG or even 50/50 for some reason). The nicotine itself is tasteless and mostly irritation free and more likely to make you feel sick/have headaches/etc. if you get too high a concentration. VG is also very moist and smooth and unlikely to irritate. Meanwhile PG is very "dry" and kinda rough to the throat, that's why people who like a good throat hit usually go for the higher PG mixes. Yeah, it's more than likely the PG. And I know when I started out no matte how little PG was in the liquid, liquid irritated my throat and dehydrated me until my body got used to it. So you may just need to give it some time and drink lots of fluids both in between and while you vape... I would say after a month or two of exclusive vaping, if you're still having throat issues, you may want to try a pure VG mix to figure out if you're just sensitive to PG itself. Only if the VG at a high nic concentration bothered me AND the PG heavy liquid at a high nic concentration bothered me would I even begin to question the nicotine content causing the irritation.