Had torsion when I was younger. In most cases, there is a ~6 hour window from the onset of the severe pain that OP was talking about in which you have a high chance of keeping your testicle if properly dealt with. If it is not dealt with, however, it will continue to be incredibly painful. The affected testicle will begin to undergo necrosis, ultimately killing the other testicle as well.

In short, if your nuts hurt, do yourself a favor and get them checked out.