I have anal pain and stool leakage after defecation for 9 months,dr said no fissure or piles.could it be internal piles the dr couldn't see?

Alternate diagnoses: Your symptoms are definitely not normal and alternate diagnoses should be considered, specifically, a fistula, which is essentially a vicious tract formed directly to the skin, sometimes hard to visualize and/or rectal prolapse, that is sliding of the inner layer of the rectum outside during/after defecation. Try to avoid constipation, see a gastroenterologist specialized in rectal disorders.