I Have Been Having Flank Pain (just Above And Travelling

I have been having flank pain (just above and travelling to below waistline) for about two weeks now. Went to a "Doc-in-a-box" a few days ago and had a urinalysis done, but everything looked fine. No blood in urine or elevated white count. Pain is varies in level of severity from about an 8 down to about a 4 ache.