What Causes Pain Between Belly Button And Hip Bone?

I'm a 23 year old female, 5'10" 160 lbs, always been athletic and I've been running for a few months, but recently am experiencing pain about midway between my belly button and right hip bone. I get it pretty early into my run, and can't fix it with breathing or resting or eating little before running. What is this and how can I make it stop?