Hi, Am A Boy Aged 18 Years Of Age. I

Hi, am a boy aged 18 years of age.
I have a problem of unfinished urination, and frequent urination, especially when I drink a plenty of water, more over I have a typhoid fever and I use Cipro, I took urine analysis, but it came negative, I took ultrasound but I have a small infection in kidney, but my doctor told me that, is not what causes my problem,

What do you advice me