I Have A Pea Sized Polyp Or Nodule On My

I have a pea sized polyp or nodule on my outer area of my rectum? Its painless but i tried to assess seems perfectly circular in shape and hard? What u think is this? I have changes in bowel movement i usually have watery stools but no bleeding. I have familal history of cancer my mom died of brain tumor and my dad died of liver cancer. Im 31 years old active and athlethic.