A few days after my son was born, my mother noticed a small lump on his back. It is a tiny bit off to the side of his spine, near the top of his back. He is a week old now and it we are pretty sure the bump is getting bigger. It is about an inch or so in length and maybe half that in width and it feels sort of hard. The doctor had him have x-rays but we won't know the results for another week and I'm wondering what could it possibly be?