Painful hard lumps on the left side around the anus and soreness in the left leg may be related to perianal abscess, thrombosed external hemorrhoids, anal canal cancer and other causes. 1. Perianal abscess: if it appears on the left side around the anus, it may cause pain in the anus or rectum area, and in serious cases, it may involve the left leg and cause soreness. 2. Thrombosed external hemorrhoids: if thrombosed external hemorrhoids are found on the left side around the anus, there may be obvious swelling and severe pain, which may make it difficult to sit or stand still, and may also cause soreness in the left leg. 3. Cancer of anal canal: if there is malignant tumor on the left side around the anus, anal pain may appear, and when the tumor presses the nerves of legs, it may cause leg pain. For those who have pain in the left side of anus with left leg pain, it is suggested that they should go to the hospital in time, clarify the cause of the disease, and carry out standardized treatment under the guidance of doctors, so as to avoid delaying the aggravation of the disease.