As per your symptoms it looks like the tooth is decayed and it has damaged the nerve. Visit a Dentist, get yourself examined, get an x-ray done. If the nerve is not damaged, it can be treated by filling the tooth. If there is a nerve damage, a root canal followed by a crown would be the line of treatment.
Next Steps
Visit a Dentist at the earliest
Health Tips
warm salt water gargles 4-5 times a day should help you with temporary relief