This could be from an anal fissure. Not knowing any more about your history, I cannot speculate much more. See a GI doctor to get a proper evaluation.

Rectal pain without an etiology should always be evaluated. However, the fact that you did have hemorrhoids you knew about, makes me think you may have some internally that you have no way of knowing about, ie. internal hemorrhoids. Best to go to a primary care physician and let them examine you, but ultimately I would strongly advise that you se a gastroenterologist

Susan E Brickle, M.D.