Testicle pain

K8
So my husband woke up this morning with a painful left testicle. He suffers with nightmares and he said he had a bad one last night so he thinks he's strained it during that.
All day he's complained about it but being a man he won't bloody phone the doctor. He said there's no swelling or physical abnormality. But he can't sit with his legs crossed and he is cautious that the dog doesn't jump or sit on him. Anyone any idea what this could be???