Welcome to your first Post! I am so sorry your wee Sir Arthur is in pain. Just like humans the RICE is the best way to go. Rest Ice Elevate Compress.
I would Not do any ball fetching right now. Instead Vet bandage, cold compress and of course rest!. You can also do an Epsom Salt bath in the bathtub and combine that with water walking in tepid water. Rinse the boy after done; dry him off - he gets some good exercise and a hydrotherapy treatment
I too am like Yorkie Mom - I'd be taking him tomorrow. It is not unusual for Yorkies to have Luxating Patella = loose kneecaps. If the kneecap goes out and stays out that is painful for anyone human or puppy
On holding a yorkie I do make it a practice to wrap one front paw near to their chest in my hand. I also cuddle them close into my body. I use a grooming table, but I tend to sit and hold the yorkie to me when I am trimming nails.
Good luck and hope wee Arthur heals up soon.