Could it be Colon Cancer?

[RobJames222]

I am 24 years old. About 1 week ago I noticed what seemed to be gas pain in my mid back. I was also mildly constipated. A few days of meal replacement shakes, eating healthier, and my bowel movements started to move again, although it seemed to be softer stool. The pain in my back has dissipated, but I seem to be having little spasm type pains all over my abdomen and chest. I think it could be from straining. My stomach is still bothering me somewhat and I get the occasional gas pain. I went to a doctor who said it seems like gastroenteritis, but I haven't had diarrhea or nausea. I can get very anxious and worried about cancer, and wondering if this sounds like I could have Colon cancer. The gas and abdominal pain is mild, and it comes and goes in waves.