Something to watch for:
If they cry or scoot it could be that their bm has stuck to the anus and will not let another one out no matter how much pressure is given. Left un-noticed it can cause major problems. I always mention every day when grooming to check that area.
If not it could be they are a baby and they do cry for attention. If you are giving your yorkie attention and she has been to the vet, I wouldn't pick her up every time she cries but maybe play some music and sing to her as you go along your daily work.
In some ways it is alot like bringing up a human child but at least they wear diapers
