I had a colonoscopy and my dr. Said I have scarring in my colon. No surgeries or injuries. Why the scarring?

Information. You should discuss that with who did the colonoscopy. There may be several different reasons. Most commonly it is related to some inflammatory condition, or possible previous surgery.
COuld be from . Prior inflammation such as diverticulitis or colitis of varying etiologies. The scarring is probably not a real problem unless there is narrowing or a stricture formation due to the scarring which can lead to symptoms of blockage. You need to ask the doctor what this means for future problems.