If the pain is along the inside of the shin, especially the lower half, then it's shin splints. If not, its another, related condition.

If you have flat feet or very high arches your'e more prone to them.

Be cautious about them. At their most severe, they are not just muscle pain, but signal complete muscle fatigue and higher dynamic stess on the bone. In high school track, I used to get them bad, but a friend of mine got them so bad it was debilitating.

Apparently, shin splints taken to their extreme can result in a stress fracture. This is what happened to my friend, and needless to say, he was off the team for a while.

We ran on concrete. That was one problem. The other problem was no rest to let the muscle recover. What sleazy said about doing some kind of cross-training on days off of running is good advice.

Stretching helps, but it doesn't replace rest and recovery. If the pain comes back the next day after running, you should definitely not run. Move into it slowly. Avoid very hard surfaces if you can.