When I first vaped I had the same issue, but it went away after a week/10 days. I have gone back to smoking, for a week or so, twice since I've been
vaping (strangely, I don't feel as devastated by some that I've done that thing), and each time I have gone back to vaping, the same thing has happened: for about a week, as soon as I inhale the vapour as far as my throat, I start uncontrollably coughing and spluttering.
I think that it's simply that the analogues damage your throat to the point that it's red-raw, but by some mechanism anaesthetise it at the same time. As soon as I've been vaping long enough for my throat to recover it's all good.