What is the difference in a mass and a tumor on the bladder my dr said it was a mass on my bladder and not a tumor?

It is tumor: All visceral masses are tumors. The question whether it arose in the bladder and extended to surface is important. Any bladder lesion invading thru muscular wall is already advanced and dangerous. Adjacent organs like colon spreading to bladder is also in need of treatment. Any mass benign or malignant in peritorneal cavity must be resected.