Bright red blood in stool? Should I get tested for cancer?

Start with your. Family doctor. They can check for common cause, organize further w/u after a digital/finger exam. The pcp can then send you for further tests.
See your doctor. While the likely cause of bloody bowel movements is usually benign, i want to stress that blood in the stool is never normal. Luckily, the cause can be easily identified with a physical exam. Often times the source is right at the anus such as hemorrhoids or an anal fissure. Occasionally, more ominous causes could be involved including inflammatory bowel disease, infections, polyps or even cancers (yes, even in young people). My recommendation is to see your doctor to help guide the diagnosis and treatment. Don't worry but don't ignore it.