So, like a lot of people I started vaping to quit a form of tobacco. For me that was dip (grizzly, Copenhagen, ect.). I purchased an Eleaf iStick 30w with a kangertech sub tank nano. LOVE the setup I must say, but once starting I was instantly plagued by canker sores and a sore throat. We ain't talking about a few tiny canker sores either, these bad boys were .5-1.0 inches wide and alllllll over my gums. Even on the back of my throat too....at first I stopped vaping for about 3 weeks until they left. Then I started again and BAM, more sores and another continuos sore throat. I searched hundreds of threads relating to this, and gained some information I'd like to share. I personally ruled out smoking cessation side effects as I never smoked and had previously quit dip for several months with no sores. That being said there were several contributing factors to eliminating my sores and sore throat. 1. PG vs VG: I bought two juices, a 50/50, and a 80/20 VG to PG...the VG based one has actually given me the most pain so on to higher PG juices. 2. juice flavors: I switched from very fruity flavors to more mellow flavors as well as taking my nic down to 6mg as I hear that fruity flavors are more prone to irritate. 3. Variable voltage/wattage: I started cooking my juice at 15.5 watts (3.2 volts). I was previously at 25 watts (4.1 volts) and found that the hotter I cooked it the more sensitive my throat became. 4. I switched my toothpaste to Biotene (contains no SLS). This has helped my dry mouth and has SIGNIFICANTLY helped my sores...........all in all incorporating all of these tactics I have ceased from getting a sore throat as well as the horrendous mouth sores. This has been an ongoing process of more than a few months, but I'm glad it's finally starting to work for me. I hope this helps