I can understand your worries. Well yes, so many
rectal/anal exams can irritate the anal mucosa and an existing
fissure can flare up. However, if the doctors cannot find any sign of fissures, then the anal irritation and pain may be due to worms in stool (so get a stool test done). Other causes could be undigested food like citrus fruits, grapes, certain spices, tomatoes, certain medicines like antibiotics and laxatives and certain drinks like beer, milk, tea, or coffee.