5 year old has cough since Oct (2 months )

Seriously don’t even know what to think anymore! My son has had a cough since before Halloween. In November went to the dr and got his tonsils checked, he had strep throat, along with runny nose and the cough. Tonsils are all better now but this cough is still here. When I finally think he’s getting my better the cough comes back and keeps him up at night from sleeping. Today he’s just coughing and coughing and won’t stop idk what to do anymore. I took him to the dr for a follow up after his strep diagnosis and the dr listened to his lungs and they seemed fine. Has a cough lasted this long with anyones little one ? It’s starting to stress me out!