Maybe due to fissures...Add fiber to your diet. Eating about 25 to 30 grams of fiber a day can help keep stools soft and improve fissure healing. Fiber-rich foods include fruits, vegetables, nuts and whole grains. You also can take a fiber supplement. Adding fiber may cause gas and bloating, so increase your intake gradually.
Drink adequate fluids. Fluids help prevent constipation.
Exercise regularly. Engage in 30 minutes or more of moderate physical activity, such as walking, most days of the week. Exercise promotes regular bowel movements and increases blood flow to all parts of your body, which may promote healing of an anal fissure...Sitz baths after bowel movements and as needed provide significant symptomatic relief because they relieve some of the painful internal sphincter muscle spasm..Consult nearest surgeon for clinical examination they will do the needful.