Kidney stones are certainly a possibility. This is more likely if there was blood on the urinalysis. The best test to evaluate for stones would be a non-contrast CT scan, and this certainly can be considered.
Regarding the abdominal pain and gas, a contrast CT scan of the abdomen can be considered, looking at the appendix or diverticulitis. I would also consider a lower endoscopy (i.e. colonoscopy) looking for inflammatory bowel disease, or any masses. Stool tests can also be considered to rule out infection.
If all the tests are negative, you may want to consider irritable bowel disease - but this is normally considered after ruling out more serious causes.
You may want to discuss these options with your personal physician.
Followup with your personal physician is essential.
This answer is not intended as and does not substitute for medical advice - the information presented is for patient education only. Please see your personal physician for further evaluation of your individual case.