CT Scan benefit outweigh the risk? I'm 23 with 3 CT scans already. Doctors concerned about chronic upper left abdomen pain radiating to back.

Depends. It depends on what your dr is concerned about. CT scans do provide significant radiation exposure. Some causes of left upper abdominal pain can e assessed by ultrasound or endoscopy, depending on your other symptoms and risks. If however, your doctor can provide good reason why CT scan is necessary, then it is probably worth doing. You can always seek a second opinion.