Mild sensitivity can occur after a bridge is re-cemented, but persistent pain and pressure for 3 days should not simply be ignored. Since you had no symptoms when the bridge was removed, the problem could be related to the bridge fit, bite being slightly high, cementation, or irritation of the supporting tooth.
Next Steps
Please revisit your dentist and have the bite checked first. If the bite is normal, the supporting teeth should be tested for sensitivity and pulp health, and the X-ray should be reviewed again.
Health Tips
Avoid chewing hard foods on that side for now. If the pain is increasing, becomes spontaneous/night pain, or you develop swelling, get it checked promptly.