I have severe stomach pain inside my belly button what can be the cause .took pt and it came out negative?

Seek Attention: Severe abdominal pain located near the belly button can have serious causes, such as, appendicitis, pancreatitis, ulcers, among others. Important symptoms to look for would be for a fever, difficulty eating, nausea, vomiting, bloody diarrhea. I advise that you seek medical attention today to discuss this formally with your physician and have an appropriate medical exam.

Belly-button pain: 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.

Many possibilities : This could be a sign of many different problems including early colon obstruction, appendicitis, torsed appendix epiploica, urachal cyst, etc. Discuss with your physician for an evaluation.