Doctor plz reply

I (Male,age-29)had been suffering from pain just bellow and 1 to 2 cm right my belly button and above(some times 1 -2cm) above the root of the penis for last 3 years and hv a urgeUrge incontinence to urination for 6th months(per 1-1.5hr after and bludder not empty fealing).one year before E.coli was found in UrineCalcium - urine test culture(less than 10 thousand).after visiting 3 doctors 29 th Sep 09 I visited an urologist and he ordered me to perform USG KUB-Prostate(no abnormality only 14 ml post void urine),SR. Creatinne(0.91mg/dl) ,Urinalisis(pus cell:1-2/hpf,Epi. cells:0-2/hpf,others: BAC Present(+) ),Routine urine culture(no organism grown with pus cell:1-2/hpf).
Then he prescrebed .2 mg veltam at bed-time for 6 weeks.
for first 10 days the the condition improved and reduce the urge to urinate also the flow improved.
After completed my 6 weeks course i meet the doctor and again complained that the flow was irregular and sometime i felt pain.he again prescribed me to take veltam .4mg for 2 months without any test or physical investigation.
6 months ago i had tested my blood sugar 2 times. That was normal. More over none of my parents and their family have bld sugar. But i could not understand the sorce of the pain and urine freq . How to rull out cystist and pros problem. For ur information i had cronic (chronic) non specific colitis 2 years before
I would like to know about the my medical problem, if i have a prostate infection or bludder problem. should i change my dr. and loking for a new dr.  and tentative time to recover from it.
plz suggest me.
thanking u to read my so long story.