During a bowel movement, when i push, i notice a fair amount of pain in the left side of my penis (not really in the testes). what could this be?

Referred pain: This may be hard stool inside the sigmoid colon pressing through the wall on a portion of the left pudendal nerve; a branch supplies the area you describe. If you have other left lower quadrant pain / tenderness, get with your physician for possible diverticulitis. I'd be interested in hearing from any gastroenterologists / urologists on here. Thanks.