VUR and inflammatory bladder polyps

Hello,

I have recently been seeing a urologist for suspected urethritis as well as my primary care doc for lower back pain.   After two treatments of Zythromax and Doxycycline, the symptom of the urethritis were still there.  In the meantime, my primary care doc had requested a renal ultrasound: the results showed that I had mild hydronephrosis and a thinner right renal cortex, compared to the left.   When I went back to my Urologist and informed him of the findings, he then ordered and IVP.  The results of that showed calcifications within the pelvis, suggesting phleboliths and old papillary necrosis in the right upper calyx.  The Urologist performed a cysto and found what he called inflammatory bladder polyps due to past infections of the urinary tract.  He also said that the IVP wass more accurate than the ultrasound and that overall, nothing was wrong with my kidney.   I have kidney pain when my bladder is full or sit upright for long periods of time.  I am really concerned about all of this.  He is treating his findings with 3 months of bactrim and if they haven't gone away then he is going to burn them out.  My gut is telling me that something is not right.  I just don't know which way to go.  I have been on the internet researching my back pain symptoms and found that that I have symptoms of VUR.  I know he will not listen to me, but how do I convince him to look into it.  He firmly told me that my back pain was not due to my kidneys and that if I keep having back pain then I need to see a back specialist.   What do I do, I feel that my health is at risk and what does all of this stuff really mean?    HELP!!!     :)