Hi , any history of trauma like from brushing or from any sharp object or have you eaten anything hot , if yes then pain is because of that and it will subside in few days
If not then you need to consult your dentist , whenever possible for you .
Next Steps
As a home remedy you can do warm saline gargle ( add a pinch of salt in luke warm water and gargle with it) , apply gummed ointment over there
Health Tips
Use soft bristle brush