I don't think it has anything to do with ecigs, but more to do with quitting regular smoking. I once had a doctor tell me that if I quit smoking then the asthma I suffered from as a child could return. He said something along the lines of smoking paralyzes the cilia (little hairs in your lungs) that would get covered with mucus which caused asthma. Quitting smoking would stop that from happening and could cause asthma to return. He stressed that this was by no means a reason to continue smoking since there were lots of other much more serious health risks from smoking.
Since I quit smoking I've had one mild asthma attack after two decades of not having any. So far I still feel way better being off the cigarettes. I would recommend seeing your doctor and getting his/her take on your current asthmatic condition.
Another anecdotal data point: My father suffers from sports related asthma, and reduced lung capacity. He smoked for 20 years, and tried many many times to quit ( using patches, before
vaping was widely known of), with varying degrees of success. Almost every time he quit, he had acute asthma attacks, and often suffered from bronchitis, both of these "improved" when he resumed smoking.
He has finally become an ex-smoker, for 4 years now, I believe, yay Dad - proud of you!