Lower Leg Pain

I know this topic has been beaten to death but I'm not quite sure that what i'm experiencing is the same as the "shin splints" I had read about in other threads.

 When I run I get shooting pain on the inside of my lower legs.  It doesn't feel like muscle strain (more like the bone hurts) and I had always associated it with low arches.  A month ago I bought a pair of Brooks adrenaline 8 shoes from a reputable racing shop.  The pain has been reduced but is still pretty bad.  I'm reluctant to hit the meds so does anyone have an answer for this?  I know ice, stretch, rest is the common answer but I'm more wondering at what point "sore" crosses over to "injured", other than the obvious showing of stress fractures in an x-ray?

 I run 3 miles 3-4x a week through the pain.  I'd like to be able to complete a sprint or two next year and eventually move up to an olympic level race but I find that anything longer than 5k leaves me limping with both legs for at least two days after.    Any help would be greatly appreciated.