Kidney stone. Pain in the left flank and left testicle may signify kidney stone disease. This is referred pain from trying to pass a kidney stone. You need a urinalysis and possible x-rays to help diagnose. See your local urologist.
Could be a stone. This specific set of symptoms *may* be caused by a stone. I would suggest evaluation by a physician to examine you and check a urinalysis and an imaging study, such as an xray, ultrasound or ct scan of the abdomen and pelvis. Other causes can be determined if no evidence of stone is found.