Oh no!! I am sorry to hear Stedman isn't feeling well, poor little guy.

Do you think he has crystals blockage? My cat had that and he would cry out and pain when trying to go to the bathroom and he wasn't able to. I have heard it can happen in dogs too. It seems to be most common in males.
I am glad you are taking him to the vet, if he has crystals he will need treatment right away.
Here is an article on stones and crystals, it says yorkies are one of the breeds that are known for it.
Calcium Oxalate Crystals in Dog Urine
I will say a prayer for Stedman and that he gets some relief soon!! Please keep us updated on what the vet says.
Hugs to you and Stedman!!