I understand why you are worried. Some pain or sensitivity can occur for a short time after RCT and after fixing a new bridge, especially if the tooth and surrounding tissues were already irritated. However, pain that becomes severe again after initially improving should be checked rather than assumed to be normal. It does not necessarily mean that the RCT or bridge has failed.
Next Steps
Please contact your dentist for a review, preferably soon. The dentist should check the tooth for biting/occlusal pressure, tenderness and the quality of the RCT, and take an X-ray if required. Sometimes a tooth can hurt because the new bridge is slightly high and putting extra pressure on it; this can usually be corrected if confirmed by the dentist.
Do not remove the permanent bridge yourself. If the pain continues or keeps returning, your dentist can decide whether any further treatment is needed
Health Tips
Try to avoid chewing hard foods on that side until the tooth is reviewed. Take pain medication only as advised by your dentist and according to the prescribed dose.
Please seek an earlier review if you develop swelling, fever, pus, severe worsening pain, or difficulty opening your mouth/swallowing.