This morning when my dughter was getting dressed she stretched her arms up and I noticed a small lump on her chest. It is high up on her chest about parallell with her arm pit. It is very small and feels like a knot under the skin.

It is definately on her chest. Should I be worried?

She is otherwise very healthy.

She's probably fine but you should have it checked out.  My husband and his daughter both have had lumps on their bodies that are tumors but not cancerous.  They did have to be removed when they became larger.  I'm sorry but I forget the name of them.  It could also be a swollen lymp node or gland.  I'm not sure where there locations are but I know there's some in the armpit areas.  I would certainly have it checked out.  Better safe than sorry!

I would say, see if it continues and isn't just a knot or something she got from another kid.  If it doesn't go away, see a doctor.

I got those when i was her age & a little older, shes growing breasts. look it up..research.