Would root canal treatment on # 11or # 14 molar teeth touches the nerve or cause any issue with sinus.i am hesitant to do procedure. feedback please.

Very unlikely.: The sinus is at much greater risk of infection with an untreated abcess of #14 (the upper left first molar) since the infection is usually just outside the sinus. As the infection grows, it can eat through the sinus floor of bone and infect the sinus.

Very slim chance: Only with #14 not #11 ther is a very slim chance that root canal treatments done to #14 could touch or penetrat the max. Sinus floor only if the roots of that tooth are into the sinus floor , your dentist can easily determine that from the x-ray of that tooth

Not likely: Root canal treatment is meant to eliminate an infection found in and around the tooth. This infection can have a negative effect on the sinus. Rct can remove an infection that began in the tooth and spread to the sinus area. It is highly unlikely that this treatment will have a detrimental effect on the sinus. For specific details about your case it would be best to consult an endodontist.