Some people have generally sensitive layer kf the mouth. In such cases apple pineapple or oranges tend to create roughness which pains. Avoid taking these fruits for sometime and evaluate yourself for the possibility of any vitamin deficiency. Many vitamin b/c deficiencies create sensitive inner lining of the body.
What you are describing is recurrent pharyngitis cause of which many infective or allergic. Your symptoms appear when you take in sour fruits, in your case they may be acting as irritants for your throat which can result in recurrent inflammation. Gargle with salt water twice a day.
Take in milk with turmeric at night.
Having issues? Consult a doctor for medical advice