For the causes of pain in the right side of the anus, specifically as follows: first, perianal abscess: generally will also be accompanied by local redness, swelling, heat, pain and other inflammatory manifestations, through the local ultrasound, CT, MRI, etc., can further clarify the site and size of the abscess. Second, anal fistula: generally this condition is a channel through the rectum and the skin around the anus, and this channel is sometimes good and sometimes bad, if there is some fecal-like material flowing out through the skin around the anus fistula, there may be obvious pain. Third, pelvic effusion: it can be caused by some gynecological inflammation, or it may be caused by infection of the genitourinary system. If you find pain in the right side of the anus, for the specific reasons that lead to it, it is recommended to go to a regular specialist hospital in time to carry out a systematic examination to clarify the diagnosis.