Persistent pain or sensitivity is a sign of continuous irritation. Few of the causes be because of a carious tooth causing abscess or calculus deposits.
Next Steps
Get a complete O.P.G X - Ray done & show to an experienced Dentist you trust or go on for a lookout with word of mouth & reference.
Health Tips
Do not try any self medication or treatment. Visit a dentist at the earliest & get a thorough examination done. All the very Best