It feels like someone is putting a knife up my ass and haveing extreme side pain on my right side i am not constipated but the paincomes comes and go?

Proctalgia or more?: Both gastroenterologists ; colorectal surgeons can help you. They will first perform a visual inspection ; digital exam after taking your history as to circumstances, duration, quality, timing of symptoms ; your risk factors. They may then determine topical treatment or ask to perform further evaluation of the rectal lining. Symptoms may prove functional (proctalgia fugax) ; warrant different rx.