wow...don't know how I missed that 24mg of nic in the OP! That is a lot of nic! And too, our body absorbs it differently when in vapor form, as opposed to smoke form......but I'm leaning more towards dehydration. Or just the simple fact that it's a known side effect for new vapers to experience sore throat-like symptoms.
If it were me, I probably wouldn't worry about it, unless the symptoms persists after a 4 days or so. If it's just your body getting used to vaping, I would think it would pass by then. If after then, I would start to suspect the PG/VG ratio causing it. Or at least, that was my experience when I first started.