Pain killers will not be of much help, visit nearby dentist n get thorough check up, gum pain can be due to periodontitis/gingivitis that requires scaling followed by gingival curettage n if sensitivity is present along with it then there might be some additional problem related to teeth itself!!
Next Steps
1.mouth rinse 2 to 3 times with mouthwash until u visit your dentist
2. regularly floss specially around the particular tooth giving trouble.
3.if unbearable then u can take analgesics.
4.get a xray done to locate n for correct /actual problem.
5.change your brush ,use soft to medium bristle toothbrush
Health Tips
avoid too hot or cold food/drinks on the affected side,avoid vigorous brushing specially around the affected tooth , remember to rinse n floss regularly !! n immediately get urself checked for correct diagnosis.