Welcome to HealthcareMagic forum
The symptoms described by you seems to be related to nerve damage
(probably the superior laryngeal nerve
). The damage to superior laryngeal nerve happens when the nerve gets stretched/damaged partially or completely while performing the surgery.
With the damage to the nerve there is loss of sensation over the superior part of the larynx
hence causing repeated gagging and coughing. Consult an ENT specialist
for a thorough evaluation of the throat.
I wish you good health