Hi and welcome,
A decayed tooth is filled only after complete excavation of caries and removal of all the discoloured infected tooth . A filled tooth should not give any pain. since you have got pain in the tooth after filling it indicates some leftover caries or infection in tooth. An already infected tooth when packed with a filling pains a lot and the infection may progress to the underlying root and the tissue leading to abscess formation and swelling.
you must have developed sore throat
because of the ice pack applied for a long time or due to the abscess drainage this can be confirmed only after clinical examination.
i suggest you to visit a dentist
and get a x ray done for the tooth which will show the remnant caries and spread of infection accordingly root canal treatment
can be done to preserve the tooth permanently.
mean time you can have antibiotic Augmentin with diclofenac serratiopeptidase
tablet 2 times daily which will give subside swelling and pain till you see a dentist. take care