Confused and nervous tumor found on my kidney...

[clarg38]

ok so I have been having sharp pain my upper abdomen two or three inches below my right breast. The pain comes on suddenly and i have to push on the spot for it to ease up. when having this pain i cant move, talk or breath deep for several minutes and feel nauseaus when the pain subsides. other symptoms are feet swelling, fatuige, nausea after eating, feeling of being bloated, pain and tenderness in back directly behind the pain the the front. My doctor sent me for an ultrasound and they found a neoplasm of uncertain behavior on my kidney, so he sent me in for a CT scan with contrast. I just got the results of the CT and they say they saw nothing. why would that be? should I have a second opinion or an MRI? The pain is more consistant than it used to be and more painful so there has to be something going on and I just feel generally ill. please help.
Thank you