The pain must be because of two reason :-
1) high point ( which means tooth is not carved properly after restoration )
2) might be possible that the infection is not cleaned properly before restoration and now it have reached to the pulp. Because of which you are having pain while eating .
Next Steps
•Visit to your dentist again , to chek high point .
•if high point is not there , go for Xray of the tooth again .
Health Tips
•avoid eating any hard food till the time of pain .
Maintain oral hygiene.