I got left lower back pain three weeks back. Along came a mild left testicular pain with it. I was made to do several tests including uti's and sonography of the kidneys. The reports are good. The general surgeon said that the back pain is radiating towards the testicle. It's been three weeks now. The back pain almost completely cured. But I still experience mild testicular pain in the left one especially when I wear boxers and the testicle is bouncing off the thigh.