which tooth is rct treated . if pain is related to wisdom tooth you need to take x ray for wisdom tooth and also for rc treated  tooth .  after that diagnosis  will be easier. 

Looks like the RCT tooth is reinfected. Get it checked by a nearby dentist. X-ray will be taken to confirm the diagnosis

Hello, Please get an X-ray or IOPA of the tooth done so that re-infection in RCT tretaed tooth can be ruled out.

Hello sir... Get x-ray (IOPA) of that Root canal treated tooth done to check any re_infection in the root canal treated tooth... Get OPG also done to check for any wisdom teeth... sometimes due to wisdom teeth, pericoronitis and gum bleeding can also occurs... if there is re_infection in root canal treated tooth, then do re-rct in that... If there is presence of wisdom teeth then get that tooth extracted surgically

Hello sir, need to examine the tooth through x-ray and also your gums status... Then only we come to a conclusion, what best treatment plan can be given...