AzrielProne, I just read your OP again and don't see some info. It may be on the thread but I'm just going to say:
You say you have been analog free for 3 weeks. You don't say though how long you've been vaping nor how heavily you smoked during that time. I'm no doctor but have had to research and learn due to my own situation. I have allergic bronchitis and started having problems the last days of April. I got scared it was vaping as I was enjoying being mucous-free and breathing deeply for 6-to-8 months vaping while only smoking 3 or 4 smokes a day. I know you've said you don't have any mucous and that's really not necessary to have the same symptoms I do. Anything that obstructs the bronchial tubes whether that be mucous build up in them or constriction of them which happens in asthma and panic attacks will cause heavy chest, shortness of breath, even painful chest and depending on how long it goes on, depeletion of enough oxygen will cause various other symptoms depending on how much oxygen the body is being deprived of. In my case, numbness of finger tips (and it changes... not always the same ones) or the whole finger. It can cause weakness in the legs and/or arms and lack of energy too... just feeling yucky. If it gets really bad, its ER time. My oxygen saturation level when I got there was 60 and above 95 is normal. So... just saying... you could be suffering from diminished oxygen.
I went to the Mayo Clinic and learned that as we withdrawn from smoking, the bronchial begin to shrink/narrow... sounds bad.. right? Well, its not because the bronchials have been stretched from tar build up smoking and once they're cleaned out, the start to return to normal size. I don't know if you were only lightly smoking and had already started into that process when you quit entirely. But, if your bronchials are narrowing and then you panic because of this new "tightness", then, yes, you might get a panic attack and they spasm like in asthma and you have a hard time breathing. Many asthmatics, my son included, have emotional triggers. Stress or emotional upset will cause an asthma attack in them.
Oddly enough, when I have lots of mucous build up... obstructing the bronchials... or an asthma flare up narrowing/restricting them, there is not enough space in my tubes to vape. Vaping as I normally do, the vapor is a lot more voluminous than smoke. In my case, it makes me cough so I get a warning not to continue vaping then. Anyway, you might want to think about these things. If you describe your symptoms to the doctor, it may trigger him to think about bronchial spasms. And you might want to mention how it comes and goes which will also make him think about spasms and just prescribed an albuterol inhaler to dialate your bronchials then. Asthmatics and those suffering from bronchial allergies use them all the time... no big deal. I do anyway. Hope that helps a little.
Edit: Gooooolly... sorry.... did not mean to write a book. I have trouble getting thoughts together typing and it comes out rambling.