I have a mysterious lump on my lower back that appeared. it doesnt hurt and its moveable when i touch it. it also is inside of my skin theres no bump on the outside of my skin or anything. what could it be?

Lumps and bumps:: Any new lump or bump that lasts for more than a few weeks should be checked out. At your age it is less likely to be something serious & could just be a sebaceous cyst or a lipoma. But sometimes it may mean something more serious. We can't tell for sure w/only a short description. To be safe see a doc about it, who can examine it &consider it in light of your medical and family history.