Hi. Thanks for your query and an elucidate history. The most probable cause for such a hard tender swelling near the anus, which becomes painful when you sit, walk sleep or touch can be due to following reasons: Prolapsed thrombosed pile. some sort of a cyst or a mass. Type of Doctor you should see: You must consult a Surgeon specialized in Gastroenterologist or a General Surgeon. He shall examine you physically to get a clinical diagnosis and to get some investigations of blood, urine and stool.