a lump on the back

Question
Hello, my 8 months old toy poodle has a lump grown on her back beside the vertebral column. The lump is soft, slightly moving when touched, doesnt hurt, not itchy and the colour of the skin is quite normal. I have visited the vet and he said it isnt possible for her to have cancer at this age which is too young. I really want to know what the lump is and is it better to observe it longer before taking out specimen from it for evaluation?
Thanks for your suggestions.

Answer
Often this is where the shots were given.  The puppy can get what is known as an injection granuloma.  Sometimes these are fluid filled sacs where the shots were given.  The vet can put a needle in it and see if there is fluid or tissue. If it gets any bigger it may need to be removed, but these go away after 2-3 weeks.