I had the same symptoms last year and it turned out to be kidney stones. I didn't want to take the time to go for the tests (I had the exact same symptoms (I can sympathize with your pain)). It took intolerable pain and severe flu-like symptoms (back pain, abdominal pain that traveled down my right leg, nausea, vomiting, severe headache, high fever) to finally get me to go to the hospital. They found the 100% blockage in my right ureter via CT Scan with contrast. Did you ever suggest this test to your doctor?
I've had a kidney stone - yikes! How long have you had this pain? Mine was gone in a few days - hope it's just that and you can get back to normal soon!
INCREASE UR FLUIDS INTAKE AND TAKE NSAIDS FOR PAIN. IF KIDNEY STONES WITH INCREASE IN WATER INTAKE MIGHT PASS