Recently I've been having on and off stomach pain (like gas pain), slight fatigue, and back pain, I thought that maybe I had pulled a muscle at work, like I probably did with my abdomen a few weeks ago, but today when I took a crap....it smelled REALLY bad. Like ammonia mixed with tar.....I'm honestly scared that I might have some kind of bowel cancer or pancreatic cancer. I'm a 25 year old man, but I'm scared I have cancer because it's been reported that more 20 and 30 year olds are getting bowel cancer.