Would I need waiver if I once was prescribed asthma medication, but was never diagnosed? If so, what is the likely hold of getting a waiver?

I notice someone else’s post on here about how he’s in similar situation and decided make a post . When I was about 14 I had persistent cough and I was prescribed a inhaler which didn’t help at all quit using went back to the doctor and told them hey this ain’t helping they prescribed me seasonal allergies meds and singulair . The thing I was worried about is that singular is a asthma medication but I was given it for seasonal allergies my father says I was never diagnosed with asthma but I was wondering if they would thing I had asthma since I was prescribed a inhaler and singular . Would I need waiver and if so what is the likely hold of getting one ? Also on his update post he talked about getting a PFT and bringing the results to the recruiters office . Would any of this effect my chances of joining