Well, if you've never "felt qi" then no sense in trying to do small circulation
Embryonic Breathing is a great way to begin to separate out the signal from the noise
Best to start out using natural abdominal breathing - you can generate plenty of qi from that method - and it will also serve to soften up the diaphragm and surrounding tissues so that if you do start a reverse breathing regimen in the future, you will get a better start because of the prior training.
If you do some work and smooth out the tissues then the sensations come more smoothly and noticeably. Generally speaking its easier to feel qi when doing seated meditation; finding movement within stillness. This will also help improve lung function so it may even assist in alleviating the asthma, although there's no guarantee of that, all up to your practice.
We dont have an embryonic breathing thread here right now, do we?