Hi Dentist Done RCT In Front Teeth Almost Last Four

Hi
Dentist done RCT in front teeth almost last four year back due to i have met with accident .but from last 6 month pain start in same teeth. i again visit doctor and he say infection in Xray then he clear infection by clearing and again done RCT remove infection . But still i have pain in same area.What i should do next.......Now doctor saying we will operate with remove flap