What is the juice you're using, if I may....some people do develop an aversion to PG-based liquids, it happened to me also, after about 2 months. My smoker's cough stopped right away, so was very unhappy with a "new cough", just couldn't shake it, my throat was sore, and the more I tried to keep going on the worse it got. Now is I use just one cartful of PG it comes back with a vengeance, including tight chest, lung pain, etc...it feels like I'm strangling. PG is extremely drying to the tissues.
Thankfully, there are juices that use VG vegetable glycerin....that was my salvation. Have had no more trouble after about four months. I've also cut back a little on vaping, just naturally more relaxed now with the whole process of cigarette replacement, so VG has not been any problem. Whew!
I also do not like to have a lot of flavors, I want strictly tobacco flavor, because some flavors can also be irritating to some people. So would recommend you try to change the liquid base you're using, good luck! Many suppliers do carry both types, some only PG, so watch carefully. Do a check, try VG for awhile, then try the PG again, just to make sure. For me there was no doubt, stay away from PG.