Maybe this might help you. I've been vaping for 40 days now. I used to be a 1.5 PAD smoker.
My 1st week I got my eGo I vaped that stuff SILLY. Noticed about day 2 my throat, ears and chest getting VERY angry. I started researching and found ECF, TOTAL LIFE SAVER. After reading posts about other people's issues I cut back on my sweets intake, avoided smokers for a week, drank plenty of fluids.
At 1st I thought I was getting strep, my throat and ears hurt soooooo bad that I would wind up with massive migraines.
I truly think your body is going thru chemical withdrawls. But because I wasn't super fond of 80%PG I wound up going to 50/50, now today you won't catch me vaping anything but 75% VG / 25% PG unless I'm super low on Glycerin or VG.
If you do buy a pre-mix say of 50/50 and you want more VG. Just get urself a bottle of Wilton's Glycerin from Walmart (it's in the party/cakes/wedding section) I just buy higher mg pre-mixes say 24mg and put it into a bottle 3/4 full and then fill the rest of the 1/4 with Glycerin, it'll save you some money as well as cut ur PG and nic intake.
I started vaping 36mg 80PG/20VG. I now vape 16 - 24mg depending on my nerves for the day
I hope you are given a clean bill of health from your doctor, and try looking into DIY even if it's learning how to lower ur pre-mix mg or add a little VG to what you already have.
Goodluck and VAPE ON!!