Got one in!!

I didn't go for my run this morning, however, I did get a mile in today after school.  My husband and I had plans to get together with friends at 5 for supper, so when I got out of school, I hit the treadmill, then jumped in the shower and was ready to go.



I'm not sure why this happens, but whenever I do a few runs on the treadmill, I end up with pain on my shins.  Sometimes one leg more than another, and sometimes both. Today, it's the left leg.  It's not even in the front and central part of the leg, but just off to the right side.  I don't seem to get this when I run outside, so I don't understand why this happens.  Anyone out there have any ideas?  Suggestions would be welcomed.