I had been having shin pain on off since September, when I was training for my first half marathon. It stayed consistent - three places on my left leg - through the race and into November. The second week of November, I did two 5k races on the same day. By the second, I was literally hobbling, and you could see the lump on the front of shin. I made an appointment with an ortho for the next week.
The diagnosis: tibial stress syndrome, caused by severly flat feet and tighten hip/calf muscles. The "cure" was three weeks of physical therapy to address the muscles issues, and custom orthotics to keep them from coming back through correction of my whole mess of biomechanical issues.
I've been a cross training queen for the past two weeks, expect for a Reindeer Run 5k last Saturday. My orthotics came Wednesday, and I took them out (along with a new pair of Brooks Dyads, since my Lunarglides wouldn't even hold the orthotics) for a short run on Thursday. They give me a strange sensation of falling foward, and make muscles hurt that feel like they've never been used, i.e. I guess that's what they mean by "glutes firing" during running.
I went out for a 5-miler this morning, and I AM SORE, from the bottoms of my feet to my lower back to my shoulders. According to the ortho, this is perfectly normal as I adjust to the new "gait pattern" and should go away in a few weeks. Let's hope so.
Do you have orthotics? How long did they take you to break in?