Hello,
It is important to know the nature of sensitivity.
If the tooth hurts when you bite or chew then either the filling is a little high and needs adjustment or there may be a microcrack in the root.
If on the other hand your tooth is sensitive to hot and cold after completion of root canal treatment, it is likely that the canals were not cleaned out properly during the treatment, or there is an extra canal that was overlooked / missed out .
I’m either case you need professional help and treatment.
Next Steps
Do warm water with salt rinses 3-4 times daily.
Take an anti inflammatory if pain is severe.
Contact me or any other experienced qualified Endodontist for professional help.
(You can message me on Practo chat )
Health Tips
Avoid eating on the affected side till a proper diagnosis about the cause of sensitivity, is made. There is a high risk of tooth fracture