When Bella was a puppy she would try to do everything Ruby did. My bed is a matress on a box spring on the floor so they can get up and down easily (i'm also in college
) and that was even too high for Bella to jump off and on because she was so small. I would try to watch her and if she wanted down i would pick her up and put her down instead of her jumping. Well sometimes she would just take off after Ruby when Ruby jumped off the bed and one time she hurt her front leg and was limping for a little bit. Later on that day she was fine, but she has done it a few times.
These little dogs can really get hurt from a height that seems like nothing to us.
I would take your yorkie to the vet if it has carried on to the next day. It seems like it may be more then just a little sprain if he is still favouring a certain paw and the fact it has changed to the back leg beats me
I would call your vet.
keep us updated!