Hi welcome to health care magic forum,
Chronic throat infection called chronic pharyngitis
Chronic pharyngitis may be due to infection,thyroid problem , laryngopharyngeal reflux
or it could be chronic tonsillitis.
In my opinion you can udergo for throat swab culture , thyroid fucntion test and a upper GI endoscopy to rule out acid peptic disease
I would suggest stop any kind of antibiotic and other medications too.
Start taking antireflux agent like pantoprazole 4o mg OD and see an ENT specialist
for review of your throat problem.