His testicles are swollen and his is in pain. What would cause that, and what can I do? Please I need advice and help!! Thank you so very much for your time in advance!!

The vet really is your only option. There are so many things this could be, and we can only guess.

No one can give you a diagnosis online, even a vet. Please take him asap, swollen testicles that cause pain is not good and needs to be seen to immediately.

Please let us know how it goes.

Good luck.

Yup, unfortunately the vet is the only thing we can suggest. I would recommend getting him neutered.