I have not had this problem being aroused when
I'm alone. The pain lasted for several
hours and my testicles
were extremely painful to touch, thankfully in the morning the pain was gone.
The next we day we met up and did the same sort of thing in the evening again, kissing for several hours.
From kissing and becoming aroused, stopping for a bit, and then kissing and becoming aroused again (and so
on) for a period of several hours, the pain returned, but MUCH worse this time.