There is chance of food lodgement even though cleaned properly on regular basis.
Luke warn water salt gargle several times a day.
If doesn't subside,
mouth wash,once in every 2 days. After meal. After use of mouth wash don't eat or drink or rinse for half an hour in order to achieve it's best effect.
Forceful Gargle in every region of mouth after every food intake, regardless the food is in solid or liquid or intermediate form.
Next Steps
visiting dentist mandatory.
you may be needing scaling.