I have had a pain near my belly button on the left side for over a year. pa ran no tests 6 month ago but said it was "stress". what could this be?

You might have, but: Pain near belly-button (umbilicus) 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.