It could be BH. I have BH during exercise and for a short while thereafter. I talked to my doctor about it and she said it isn't anything to be concerned about unless it lasts for a couple hours. Keep tabs on your exertion level and stay hydrated!
Agree. Sounds like BH. I get it when running uphill or walking up stairs. My midwife said it is because the uterus is tired. Hydration and rest if persistent and don't go away when you stop. Otherwise nothing to worry about.
Re: stomach hardening during exercise?