X-rays are where I would start. Depending on the results you go from there. For now I would limit her activity - no running whatsoever.
Will definitely keep her at a 'walking' pace until the X-Rays come through. I let her run around with a few dogs at the park a couple days ago though... sure hope that didn't do any harm.
// edit - what's a reasonable price for X Rays? I realized this will vary by location & vet, but just curious of a general idea.