check your medications. Maybe if you’re taking an ACE-inhibitor for hypertension may cause cough.
Lung Cancer
Reactive Airway disease-COPD or asthma
GERD-reflux. may improve with meds, CPAP if caused by sleep apnea.
Allergies.
there’s a list you can go through
Evidently not the problem in this case, but I don’t understand why lisinopril is prescribed instead of the angiotension-II inhibitors like losartan, which have other protective effects. There is some cost difference, I know.