It's seems tender and sore around my stomach's mid section, especially around the belly button. i'm not in any severe pain. ?

Consider these...: Belly-button (umbilical) pain may originate locally due to infection or herniation, or be "referred" from another abdominal location like the appendix. Signs/symptoms of concern include: local redness, drainage, umbilical bulging that can't be reduced with gentle pressure, fever, vomiting, change in bowels, generalized abdominal tenderness (suggests peritonitis), worsening pain. Get checked please