Well the first thing is to make sure that it isn't a twisted testicle, because that can be dangerous. However it seems that has it is not an acute situation, so likely the pain is caused by some other issue.

I did want to weigh in that I have had lower back pain from herniated disks for almost 15 years. At the same time, I have had increasing pain in my testicles, sometimes to the point of being debilitating. I have seen GPS, urologists, and even surgeons. I have had my penis and testicles imaged at least 6 times. The only thing they ever found was two hernias. The hernias were repaired expecting the pain to go away...and no....it didn't.

The fact is...I have always linked my testicle pain to my LBP. I know there's no direct link, but in that area of the body all the muscles used to keep a human body upright have to work together and if they aren't working right in the back, that can out a strain elsewhere.

In the past I found an interesting medical article which actually looked into this and did prove a linkage. I'll see if I can find it and post a link.

I think that Webgoji may have a point with the underwear. Change yours for something loose or perhaps even go commando. My pain has gotten to the point that I rarely, if ever, wear any because of the pressure points and discomfort.

Good luck. Just to let you know you aren't alone and ways you could work around the pain.