Please mention whether the crown is placed. It might be a gum pain due to food impaction or might be high points, Do scaling and occlusion correction . Gums are sensitive during pregnancy and highly reactive.
Next Steps
Please visit the dentist and check for the above mentioned causes and go for a treatment plan
Health Tips
Maintain good oral hygiene habits.
If there is no relief in this, then you can redo RCT.
Hope this helps you mam.