Hi.. Can understand your concern.. As per your complain as you had a broken tooth which you had pain also shows that there must be some infection in the tooth leading to infection reaching the nerves present in the central portion of tooth known as Pulp and irritation and inflammation of nerves causes pain. There is also formation of pus below the root apex of tooth forming Dental Abscess.. After the root canal is initiated and after the sitting if there is some infection and pus left inside and the tooth is sealed with temporary filling there are chances that the pus present inside causes pressure on the nerve fibres in that area and as there is no escape way for pus when tooth is sealed the pus get collected in the soft tissues causing swelling.. You need not to worry, if possible go to you dentist and get the filling removed and under local anaesthesia get the the root canals cleaned once again and you will get relieved of pain and just get a piece of cotton placed in the cavity.. Continue with the medicines and in next 2 to 3 days there will be relieved from, pain as well as infection and swelling will also reduce considerably.. Then the further treatments can be accomplished.. Hope this information helps.. 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.