What would cause testicular pain?

Have him go to clinic or doctor, it could be a strain or infection.
It could also be cancer, I know it is better to earlier rather than later. Doctor told me I was lucky to go in when I did and a month later I might not be here. That was 27 years ago.

Is he in to rough or hard sex? some times you can hurt your balls if you are trying to use your dick as a battering ramm.

Also, some times testicles just hurt. Maybe he lifted something heavy, or stretched or pulled a muscle, and now he will have a dull ache in his balls for a couple of days when he moves or sits a certain way.

I’m not a doctor, and my advice with medical issues is always to go see a doctor, but if it were me, I would probably leave it another day or two.

Check his underwear, he may be wearing undies a size to tight for him.

An infection or strangulation or muscle pull are pretty common. I had a strangulated teste one time that hurt/ached like hell and is not something to mess around with. Apparently too much bike riding and loose boxers may have allowed the teste to get twisted around and I had to take care to reposition it and watch for lack of improvement from the pain. It did go away in about a week. Muscle/groin pulls to can cause a pretty rad pain in the teste too. If he is under 35 he is in the right age group for testicular cancer. A self exam should be done to look for lumps. If the epididymis is puffy or painful then an infection may be the cause. Any swelling, redness or heat from the sore area should be examined ASAP by a doc.

YO

My husband’s chief complaint before discovering that he had two herniated discs in his lower back was that his testicles were sore and swollen.
Could be a lot of things. Best to have it checked out, of course.

http://familydoctor.org/online/famdocen/home/tools/symptom/539.html

Testicular torsion?

An infection?

Probably not common. I don’t really have a medical background, but I’d have your doctor check for a hernia.