I would not want to speculate about what that pain is. Especially since it only happens when you run. What has your doctor told you? Heartburn usually is experienced much later on in your pregnancy. Usually the third trimester. The tired feeling usually ends after the first trimester, and you get a burst of energy from the 13th week to about week 30. Then you feel tired again, mainly because the baby is getting larger and you just feel uncomfortable.

The pain may go away. But if it doesn't, focus in on what you can do rather than what you can't. Otherwise you'll lose focus of how wonderful the experience of pregnancy can be. This can be an opportunity to pursue fitness activities you may not have otherwise tried.