Abdominal pain is such a common symptom for so many conditions that connecting it with cancer is more paranoid than reasonable. Nonetheless, cancer is a still a possible diagnosis so you can request the diagnostic procedures necessary to exclude it. An ultrasound scan, CT-scan, gastroscopy and colonoscopy are the mostly frequently used exams for proving or excluding colon cancer any other abdominal tumors as possible diagnoses. An occult blood test of the stool is also useful. At your age (late 20's), colon cancer is very rare except for people who suffer from congenital polyposis of the colon.

You can consult your GP to request the exams and later an internist, if necessary.