When you sit down, the anus appears to the top of the pain to consider the symptoms of anal fissure, sit down to stimulate the anal fissure wounds lead to pain and discomfort, the nerve around the anus is relatively rich, the pain is a relatively common phenomenon, it is recommended to go to the hospital to check and timely treatment of anal fissure, usually with warm water sitz bath, to solve the treatment of constipation, the symptom will gradually and slowly get better. Thrombosed external hemorrhoids or internal hemorrhoids embedded can also appear the above symptoms, can be found in the anus around the swollen hemorrhoidal nucleus, need to take oral or topical pain medication, in serious cases, go to the hospital for surgical treatment. Inflammatory infections around the anus can also appear pain when sitting down, the localization will have obvious redness, swelling, pain, you can first use dilute potassium permanganate solution sitz bath, visit the oral anti-inflammatory drugs, try to go to the hospital to check the specific situation.