Hello Good Evening,
According to your symptoms and investigation you have advised, you are seems to have pain originated from kidney
and urinary bladder
For evaluating patients with voiding dysfunction, noninvasive test to measure of postvoid residual urine volume (PVR) by USG is also called USG PVR.
It is useful in evaluating patients with lower urinary tract symptoms
(LUTS), potential urinary problem as a storage disorder, voiding disorder, or a combination of both. It is not uncommon for abnormalities of the voiding phase to cause problems in the storage phase, for example, the occurrence of bladder overactivity with bladder outlet obstruction
So you should go for advised test, it cause nothing harm to the body and will help you in diagnosis followed by management.
Dr. Naresh Jain