You definatly have symptoms of a hemmroid- itching, blood, and a bump. However, I would keep a close eye on this and consider visiting your doctor just to be on the safe side. Like Morecambie said, colon cancer is very rare in people under 40 but not unheard of. Are you having any additional symptoms such as narrow stools, unintentional weight loss, or abdominal pain?
The standard answer is "rectal bleeding is never normal so get it medically checked out".
Hopefully your doctor can diagnose one of the more minor causes such as haemorrhoids or anal fissure but if the diagnosis is "presumptive" (i.e. "well it looks as if it might be.....") then ask for a colonoscopy as the most informative test which should reveal the more sinister diseases in the unlikely event (for your age) that they are present.
regards
Morecambe