I couldn't find anywhere the nicotine levels you are purchasing.
First of all, nicotine as most of know, is a vasoconstrictor. In short it means that it causes poor circulation to your muscles. The biggest organ it effects is your heart. Nicotine depletes the oxygen in your lungs. To counteract the effects you must exercise, eat certain foods, etc. It sounds like you did all of those things while smoking, which is why you did not feel the effects of analogs.
To recap all of the other issues, I do not think it is asthma, glycerine, etc. It may be from the fibers, if you are smoking a 3-piece, but since I started cartomizers and drink plenty of clear liquids, the problem has stopped for me.
My opinion, if you think it is the vaping, it is the nicotine. When you smoke analogs that are, lets say 18 mg, you actually only ingest 1 mg into your body, which your liver metabolizes and filters and the main part of the drug goes to your brain in like 2 seconds. This is why we get the buzz and stress relief. Nicotine also increases you memory and brain function. Without getting too medical, there are so many reasons it is addictive and enjoyable. Back to my point about the consumption, with e-cigs we do not know how much nicotine we are ingesting because it is not being burned off like analogs. Lets say you try to match you analog intake with e-liquid in the same mg, you will be ingesting more nicotine, which does deplete the heart of oxygen and will cause sob. Not everyone's body reacts the same to foreign agents. Unfortunately, this just may be something your body can not process properly. Also remember that nicotine is a natural insectacide and extracted and used on crops. Nicotine is a poison no matter how you chop it up, smoke it, vape it, etc.
I am not trying to be a killjoy, and I will continue to vape because, in my opinion, anything is better than 400+ carcinogens found in analogs. I know that I still have cancer risks just by breathing air, but I am trying to prevent doing it too myself.
I also hate to jump on the bandwagon all the time with China, but seriously if they put plastic in baby formula and lead in childrens jewlery, what makes anyone think that e-cigs are any different.
In conclusion, good luck with whatever you decide. I hope you can quit everything all together. Unfortunately, I am just one of those type A's who takes all vices too far and will just substitute one for another and/or make excuses for it. HAHA!!!!!
P.S. I do not think it is all in your head.