Can the zpack help an upper respiratory infection with someone with asthma? or do i have to let it run its course?

Depends: if this was truly a bacterial infection, which most are not, it might help. If not it's just a waste of time/money/med that will have whatever side effects you are otherwise prone to.

Chest Infect.+Asthma: Good day; As a long time asthmatic who is predisposed to upper respiratory infections, I find the zpak effective. May require additional days'dose until symptoms disappear before stopping Azithromycin. I infection not over, I ask pulmonologist to prescribe Levofloxacin. Feel better