Hi.. Can understand your concern.. As per your complain pain after a dental filling occurs in case if the infection was too deep and the cavity which was made after removing the infected portion of the tooth to retain the filling has caused opening of the nerves and blood vessels present in the central portion of tooth in a small chamber known as PULP CHAMBER When the nerves gets exposed and the filling is done over it, leads to inflammation and irritation of the nerves causing pain.. The inflammation leads to formation of inflammatory exudate near the root tips of the tooth which accumulates in the soft tissues causing swelling.. I would suggest you to consult a dentist and get clinical evaluation and x ray done to rule out the exact cause of the pain and get treated accordingly.. In case of nerve exposure Root canal treatment along with antibiotics and painkillers will provide relief.. Do not hesitate to go to the dentist as the pain which you will keep experiencing without treatment will be much more dreadful then the treatment as the treatment will be done under anaesthesia and you wont have pain.. Hope your query is solved.. If you find the answer helpful please write a positive review and click on find this answer helpful as a token of appreciation.. Thanks and regards.. Dr.Honey Nandwani Arora.