Shin pain- don't think it's shin splints.?

I developed pain in both my shins and at first I thought it was shin splints. I gave myself a week off of excessive exercise. I looked up ways to strengthen the muscle and did those exercises. I ride horses so I have to keep those muscles strong anyways. For the past 3 weeks, the pain in my shins has been pretty constant, before and after riding my horse but not during. Running is out of the question- the pain is so severe that my legs sometimes feel like they're going to give out- so I stop running (logical). I've figured out how to go up stairs so they don't hurt half as bad by not straightening my legs. Going down stairs is pretty much a crap-shoot as to if I'm going to fall or not, I feel like I can't support myself. Should I head to the doctor and maybe some physical therapy? Any ideas? I've done research on shin splints and the symptoms involved and it doesn't seem to be leading up to shin splints. Thanks to much for any input!!