Hello sir..          The pain is due to decay of the infected tooth which reaches the pulp layer(nerve layer)         First and foremost thing is to take an x-ray (IOPA)        If pain is persisting continuously an Root canal treatment procedure should be done       There is no point of refilling the cavity which will not give a permanent relief..

If pain is there then you may have to go for rct !!

Take an xray

it may need refilling or if caries is invovlving the bloodsupply of tooth  then root canal treatment.

Visit your dentist for a check up and x ray for the tooth. That will provide an idea regarding any decay below the filling or if there is fracture of the filling.

Get iopa( small x-ray) done

Take an xray and we can decide about saving the tooth

It may require a root canal treatment. Get an X-ray done to check the tooth and your dentist will advise you accordingly if you should do a filling or root canal treatment