Iwoke up this am with my lower belly hurtn. Right under my belly button. When II stretch it hurts worse. Put my hands over my head. Wats wrong?

Pulled muscle maybe. Pain that is worse with stretching means it could be just a muscle pain. If it is better not stretching or seems worse with certain movements and positions, then it is most likely a muscle strain. If it has continued to worsen or hurts to pushing in and if you are worried, then see your physician.