I have a hard painful lump on my descending colon that was discovered yesterday by my GI doctor. I have to have a colonoscopy in two weeks, but the doctor seemed quite concerned. I have been dealing with chronic constipation (up to two weeks at a time), red blood in my stool, and mucus in my stool. Lots of nausea and a feeling of "soreness" in my abdomen. I have been incredibly fatigued, as well. This lump is about a nickel in diameter, it hurts when touched. The doctor said it's much to high to be an internal hemorrhoid.My question is, when should I begin to worry about cancer? I am only 26 years old.