At your age there is possibility of third molars (wisdom teeth
Sometimes due to lack of space, these erupting teeth cause pressure leading to pain.
If there is no enough space for these teeth, it will cause food lodgement and infection
in gums (pericoronitis).
You may need to get x ray
done to check for the space available for this tooth,
1. If there is space, you can go for conservative treatment like cleaning and medications
2. If there is no space, you need surgical removal of this tooth.