Hello ,before advising you something o would like to know few things
1.this pain is relevant with sane tooth or it’s been bcoz of injection (local anaesthetic ) given for RCT
2.some times it’s happen if there is high point while you touching with opposing tooth
3. Something this kind of pain happens as single visit root canal as you kept open your mouth for long durations
Next Steps
Visit to dentist as early as possible mean while you can have the analgesic
Health Tips
Don’t eat much from affecting side
Don’t take sleep from affecting side
Just apply ice on cheek and neck region