Would someone feel pain when a colon is perforated or can it be a painless and unidentifiable injury?

Usually painful: Perforation is usually extremely sharp and painful as the colon tears. After perforation pain may subside for a few hours before becoming constant and progressively more severe as bowel contents and bad organisms infect the abdominal cavity.

Colonic pain: If one had perforated colon, bacteria from the perforation (P) would infect the peritoneal cavity and the pain associated with this P would be intense and be accompanied by a fever. People with these symptoms need to be seen in the ER. If there is no pain nor fever, it is very unlikely that there is a P present.