Thanks for asking the query,
Tooth pain indicates bacterial infection that had spread to the pulpal tissue,
Since you have a old filling came out there are more chances of getting infection and sensitivity .
I would suggest you to take an x-ray of the tooth this will give the periapical condition of the tooth.
You have to go for Root Canal Treatment of the tooth , in this procedure the pulp tissue is removed and the tooth is devitlised and sealed to apex . Placement of prosthetic crown is necessary after this procedure.
Since you cannot visit the Dentist
now you can start with course of antibiotic and analgesic
take tab odoxil
500mg TDS , tab Zerodol
TDS for 5 days .
Maintain a good oral hygiene , use chlorhexidine
mouthwash gargles twice daily.
Hope this helps out.