A small lump on the inside of the anus does not necessarily mean you have genital warts. Other diagnoses should be considered, too. The lump in the anal area might be due to hemorrhoids. Hemorrhoids are swelling and inflammation of the veins in the anus. The lack of pain might indicate that the hemorrhoids are at the beginning stage. Also, an inflammation of the many skin and mucosal glands in that area might have caused the bump. It is hard to say what the lump is without seeing it, thus you might want to visit your doctor and have him see it.