So good that you've stopped smoking. I only smoked as a student then again as a mature student in my 40's.
I dread to think what I'd been like if I'd clocked up more years of smoking . As I've learnt here, other factors can be involved ie childhood illnesses, working environment, over use of chemicals, living in damp unventilated atmospheres.
I had asthma as a child then again diagnosed with it 9 years ago but I realise now that it never really went away.
If only I knew then what I know now - knowledge and education about it is the key.
Sadly 3 of my children smoked. One stopped a few years ago, the 29 year old recently stopped but William still does (plus much marijuana which is very very bad for lungs too & he's the only one with asthma grrrrr).
You keep well, learn as much as you can, do PR course, take up all the suggestions above and you will give it your bestest shot at staying mild.
I haven't time to read through again but Manuka honey helps fight infections plus Vits C, D3 to keep your immune system thriving. Good luck