So, after a solid day and then some of recovery, I've come to the conclusion that what I originally assumed was a shin splint is much more likely a stress fracture.
I've had shin splints before. About ten years ago they were the plague of my dance existence. I wore high socks for some added compression and did toe taps the whole way to and from dance until my shins burned with exhaustion. But they went away and (I thought until Saturday) stayed away. Shin splints are basically injuries where the muscle starts to rip a little from the shin bone. It hurts, but is fairly easily repaired through various exercises, rest, stretching, and massage. And they hurt almost exclusively when you're using them (or working on trying to fix them).
Now, after paying attention to it, I'm fairly certain that the pain in my lower left leg is not a shin splint, but in fact a stress fracture. On a whim I looked them up, as I wasn't very familiar withe them, and was surprised at how closely they described what I'm feeling. Stress fractures can result from a variety of things (malnutrition, osteoporosis) but one of the more common causes is overuse (Hey! That's me!). So, say a person ran a marathon and then hiked 15-16 miles up and down a mountain in the space of about a week, they might be in the susceptible bracket for a stress fracture unless their body was adapted to those kinds of uses.
Long story short, my leg still hurts a great deal, at rest or in motion, hasn't responded to massage or stretching at all, and the pain in fact doesn't even feel muscular at all.
Without actually going to a doctor and getting an MRI or a bone scan, there's no way to confirm that it is specifically a stress fracture, but I'll admit that I'm a little hesitant to go to the doctor at this moment because I don't see much of the benefits in this particular case of doing that. When you go to the doctor, they give you the various tests to confirm the stress fracture, and then usually prescribe you to several weeks of rest or certain types of exercise only (like swimming and biking). In some cases they prescribe compression boots and/or crutches to help you completely remove yourself from weight bearing on the injury. Now, I do think it would be nice to know, definitively, if I have a stress fracture, but aside from the boot and crutches, I think I can take the necessary precautions otherwise gained from visiting a doctor. Am I wrong in assuming that? Any anecdotal evidence to suggest I actually go to the doctor?
So, at least at the moment I'm planning on taking a break from running, which means I'll need to come up with an athletic equivalent soon, as I think I'll go crazy if I don't continue to get some good exercise in on a regular basis. I'm considering swimming and biking as alternatives. The first requires a gym membership, so that may loom in the near future.
Update: I've decided to go see a doctor. Only good things can result from doing that, right?