That's what I used to say...until sucralose and aspartame were identified as the culprits behind a number of strange 'auto immune' problems my body had been manifesting during 15+ years of using artificial sweeteners. Once I stopped the artificial 'FDA approved' sweeteners, allergies cleared up, chronic ear rattling cleared up, skin wounds that wouldn't heal finally cleared up, joint pain went away, vision stabilized to the point I could get a good eyeglass prescription, tongue splits (and taste bud inflammation) cleared up, muscle ticks went away, circulation through hands and feet was restored...I can go on for a few more lines, but I hope you get the idea.
Doctors had attributed most of those problems to 'the aging process', and I BELIEVED THEM. Now I know better. I'll never recommend aspartame or sucralose to anyone, because in my experience, they are an expensive poison that slowly accumulates into subtle discomfort on a variety of levels. Once those symptoms appear, doctors probably won't be able to identify their cause, and will diagnose them as 'auto immune' processes. (Over a period of years, I spent more than $3000 getting the 'auto immune' diagnosis, plus the cost of prescriptions, over the counter meds...plus the continued cost of buying the artificial stuff.) Once I dropped the aspartame and sucralose from my diet, LIFE BECAME PLEASANTLY BEAUTIFUL once again!

(ymmv)
At any rate, I HOPE you never experience what I went through...but millions of people ARE affected; many of them don't recognize the connection...yet.
Good luck!
I can speak to this, due to a lot of experience, similar outcome as you. I will say this heartily: EVERY body is different. Therefore the "they say...." may be something that will be true for you, or not.
The recognized "gold standard" for {food} allergy is a hypo elimination diet, which took a year out of my life and required tremendous discipline. You start off only eating 7 or 8 foods for about 28 days, and can only add 1 thing in every 72 hours so you can see how this could take a year+.

You keep a journal and you cannot cheat.
Long story short, all the chronic and debilitating health problems I had, and for which I was medicated for, resolved. As a matter of fact, in terms of my reflux, all the things they "said" I couldn't eat all those years were not the culprit (OJ, tomatoes, citrus,) but were just the straw that broke the camels back because the REAL offenders for me were 2 other foods. Once those 2 were stopped, I could finally eat everything else! You not only find out what you are sensitive to, but also what foods make YOUR body work most efficiently. (dairy was my killer, not lactose, but the protein in milk; this is how they send you down the wrong path...I was lactose tested and passed, so "they" figured I was okay with dairy...and so I continued to due MAJOR damage for antoher 15 years while taking Nexium to supress the "symptoms". )
The other was wheat gluen (my arthritis is about 80% better now).
Because I know how this works, it can work with ejuice as well. anyone with suspected sensitivity must do this carefully and by process of elim. It could be flavors, it could be PG or VG, it could be the Sucralose or artificial sweetner, etc. You will have to isolate these things and experiment, without cross-contamination.
Which brings me back to sucralose. Since this substance often creates allergenic (inflammatory) responses in some people, it follows that it could create the same responses if it's in e-juice, not just your food.
(And not related to ecigs, but for any kind of chronic condition, find a good nutritionist who is willing to work with you on an allergenic food elmination diet. It changed my life, drastically!) I've been asked by people who are using walker or wheelchairs, or have reflux disease related esophageal damage, and when I would mention not being able to eat stuff, like bread, for months on the experiment, they say stuff like "I could never give up my bread" and I want to say "but you have given up your mobility, you're in a wheelchair." but of course I don't. They have to decide for themselves)
Sucralose may or may not be bad intrinsically, but it could be bad for "you."
Which brings me to next question:
HOW do we know which ejuice makers don't use sucralose, and that it is not in the flavors, either.