My Husband Had His Left Kidney Removed 5 Years Ago

My husband had his left kidney removed 5 years ago due to cancer. He has had discomfort in his left testical which seems to get worse as time passes. He notices this more when the weather is cooler. ( he says it feels like he has been kicked in the nuts) This appears to be intermitent. He has just had an ultrasound. He was old there was no cancer but there was something unusual on the scan. Nobody seems to know what?? Can you offer any information as to why this is happening?

Regards