You see what doesn't make sense to me is that you say you get this tightness of chest in the morning. But for the rest of the day, you have no problem vaping.
If you were vaping juices that give you a tight chest or were problematic for you, you would experience those problems at other times too.
So this tells me that it's something about you, not necessarily the vaping juices or gear.
Maybe your body is so used to the smoking that you manage that quite easily. But because the vaping is something new, your body has a problem with it in the morning, when perhaps your chest is tight just after you wake up.
Maybe @DoC has some pearls of wisdom to share for someone who wakes up with a tight chest and finds they can't easily vape but they can have a real cigarette. But then later in the day, they can vape without a problem.
@Silver That's also what confuses me - I have no problem at all during the day, I'm vaping the whole day (I work at home) and have no issues during the day or evening.
That could be it - I'm used to have a smoke in the morning and my body needs to adjust and get used to vaping and not smoking.
Or my body is still getting rid of all the toxins from all the years of smoking.