Hello,
It seems the filling after root canal treatment has destructed. So might be reinfection has occurred. Go to your dentist you might need ROOT CANAL TREATMENT get done again in the that tooth. Till you visit Dentist you can take analgesic like BRUFEN 400.hope this helps. Thanks for choosing practo! Regards Dr Ravin Shah
Next Steps
Visit Dentist and get X-ray done of paining tooth
Health Tips
Dont chew with that tooth to avoid pain