Episode of wheezing when inhaling deeply?

[Dionpl]

I am 25, female, i have mild asthma. For like 2 days i had a slight cough that i thought was allergies, also some phlegm, and the next day for like an hour i had wheezing on inhale when breathing deeply, like a squeak sound at the end of the inhale. I went to the pulm doctor, he listened to my lungs and did spirometry and he said just mild obstruction. Im worried sick i have something else because i saw the wheezing on inhale linked with severe diseases though, should i continue investigating? The sound hasnt come up again so far (its been a month)