@heartyrainbow A persistent cough can be caused by many things, among them are post-nasal drip - mucus from the sinuses flowing down the back of the throat. Or it could be gastro-esophogeal reflux where stomach contents leak upward, an over-reactive airway, allergies, or even vocal chord dysfunction. An ENT (Otolaryngologist) or an allergy specialist may be helpful.
Have you seen one?