OK, so making the transition to a more natural running style isn't all unicorns and rainbows. It hurts a bit too.
In the past, when I've had to stop running it's been because I was out of breath. This time around, my breathing and heart rate are level, even though I'm running faster (a relative term) than I ever did before. It's my legs that are holding me back. My calves get tight and if I go too long, I start to compensate and my form suffers (which my body communicates to me in the form of shin splints).
Here's the good news: my back feels great. My chiropractor told me I'd never be able to run without pain. Yet with my inov-8's and a more natural form, I'm running back pain-free. And while my calves are sore, my breathing has been so good that I know I've become more efficient in a fairly short amount of time, which is really encouraging.
I know that with time, my calves will get stronger and catch up to my lungs. To help facilitate that, I'm being diligent about stretching, I'm strength training on my off days, and ice has become my new best friend. If you have any other tips, I'd love to hear them!