Baby coughing

Hi Mummies Recently my 5 months old baby has been coughing whenever she is asleep (occasionally when sitting as well) but most of the time when sleeping. She is not sick (no fever or flu) but she has been drooling alot, not sure if that is the cause? She can cough quite hard at times like till wana vomit 😢 But she can still drink milk and play. Wana know if any mummies experience such?