Thanks for asking the query,
indicates infection in the gums known as gingivitis, it occurs due to poor oral hygiene
, plague and calculus deposition , systemic conditions and hormonal imbalance.
I would suggest you to visit the Dentist
and get the checkup done, take an x-ray of the tooth which is having pain, go for symptomatic treatment of complete mouth scaling nad polishing.
Tooth which is having pain can be treated with root canal treatment
Brush the teeth twice daily, use antiseptic mouthwash rinses.
Take multivitamin suplements.
Drink plenty of water and keep yourself hydrated.
Hope this helps out.