Why do I have a sore throat?
If it feels like you've swallowed sandpaper, your coil is likely dying (the infamous dry hit) or you're dehydrated. Vaping dries out your throat faster than a summer in the Sahara. Drink water, change your coil, and stop vaping if it burns—we aren't here to suffer.
The technical cause is often a clogged coil burning the cotton instead of vaporizing the liquid, releasing irritating acrolein. Another reason could be a slight intolerance to Propylene Glycol. In this case, opt for "Full VG" or Vegetol-based liquids to give your vocal cords a break.