Lower left abdominal slight pain after bowel movements how likely is it colorectal cancer?

Insufficient info: If you are 22 years old, it is highly unlikley that you have colorectal cancer, unless there is a strong family history of early onset of the disease.

Need more info: Such as age , duration of symptoms, details of pain but in general this is not classic if you will for colon cancer. If your age or history is appropriate then a colonoscopy will give the diagnosis or peace of mind.