It could be a might inflammatory condition, like a mild pharyngitis, or it could be because of gastric reflux. The only way we can be certain is if we do an endoscopic examination and assess the throat. Until then, you can gargle warm water with a pinch of salt added, 2-3 times a day for symptomatic relief.
Next Steps
In person consultation with an ENT surgeon, at a hospital with facility for endoscopy