You might be required for another dental check-up to see if any adjacent tooth has got decayed. decay with pain indicates deeper caries which may or may not require RCT. Best thing would be to visit dentist and get yourself thoroughly checked. Also check why you are getting prone to decay, may be other issues like poor oral hygiene, crowding of teeth, any underlying medical illness etc
Next Steps
please visit a dentist, do not delay as you are already having pain
Health Tips
you can take ketrol-Dt twice daily post meal which will only subside pain for 3 to 4 hour if care not take for the tooth giving you trouble.
take care