I have a friend with a whole host of health problems, including severe seizures. I was on the phone with him one night, when he said hang on, and I hear "oh, ow!" And then he starts screaming like he's being murdered. I thought it was like an extreme seizure. Turns out, testicular torsion. I felt so badly for him.
He is. Poor guy, though. He's had a lot of stuff in his life. He also had vericose veins on his dick and balls, and the pee hole was in the wrong spot when he was born.
And no, I'm not sharing info he'd want hidden. He's very, very open this stuff and tries to destigmatize. Just in case anyone was concerned.
Apparently, some people are more likely to have it happen because of an inherited trait. Find out from relatives if it's happened to them? You're probably okay, otherwise! There's a surgical fix if you do have that trait, too.