Hi sir. Gum swelling and mobility in tooth could be because of infection or food deposition or even tooth decay. We might need to make an Xray to know the condition better. In most of the conditions, the tooth can be saved. you will need to visit a dentist for further treatment. And, Overall gum infection can be controlled by a procedure called 'scaling' or 'oral prophylaxis' that is done to clean the teeth and gums, and following preventive care can help regain the original gum strength.
Next Steps
Mild painkiller can be used. Its better to get the medicines prescribed by a dentist, based on your medical history and present tooth condition. Plz Visit a dentist as soon as possible.
Health Tips
For time being, u can try warm water and salt rinse and simple gum massage to give you relief.