Ok so i was sitting on the couch with Layla and Chance and when rubing Layla i noticed a lump the size of a walnut on the back of her neck between her shoulders. It moves around and is squishy. I called the vet and he said that sometimes happens at the site of injection for shots....Said he will see her tomorrow but he doesnt think it is anything to worry about. She got her shots last Thurs. Does this happen often??? I am scared!!!!