The first thing to check is make sure you're not "backwards breathing." Make sure when your breath goes in, your bellybutton goes out. Lots of people do the opposite, and their insides get all squished and abused. No wonder it hurts!<br><br>
There are lots of other causes. Someone else may be able to chime in with specific remedies. Mostly, if you're patient they will just stop showing up as you run more.