Yes, it's accurate. In fact it's exactly what happened.
It was 23.30pm, I was back from a trip in Austria (what a beautiful country btw). I wasn't feeling bad, I was just feeling kind of tired and, for some random reason that I can't really explain (let's just say i'm retarded), I took one of these niacinamide pills that were sitting quietly in my fridge. The brand is Metabolics and, it's 500mg per capsule -- which is more than 3000% of DV, something I discovered right after taking it. I went to sleep right after that.
At 6am I was woken up by a pain. A pain, yes, in the balls, more precisely at the root of my right ball, on the side. I see no visible redness or anything.
2 hours later I'm in the ER and every nurse on the block has touched my balls (I'm not bragging btw, it’s a hell of a pain). To their disbelief, there's nothing. I get the impression that it's a blood vessel problem on the inside, but I could be totally wrong. It completely disappeared after 2 hours, and nobody understood what it was. It was the only occurrence of ball torture in my life (so far).
I may have slight liver/heart/cholesterol problems but nothing significant and definitely got deep gut problems from a retarded diet, which I fixed. Aside from this I'm normal weight and overall healthy. My diet at the time was like 20P/40F/40C. I also wasn't sleeping in a weird position.
Was it related to my niacinamide intake? It might not but the coincidence is weird. I know B3 can act as blood thinner, and also acts on HDL cholesterol...
Do you guys have any ideas what it could have been?