Never had this happen to a Yorkie but my cat Lily had to have several surgeries on suspicion of a blockage. Turns out she had a piece of gauze sponge left in her abdomen from when she was spayed...
BUT now 2 years later...she's a happy VERY VERY spoiled little kitty with NO issues...
GOOD LUCK and I hope EVERYTHING turns out well! Hopefully there will be no incision needed!