Thanks for the query.
Your symptoms are suggestive of UTI.
One of the common reasons for a sterile culture is if you had taken the dose of antibiotic before giving the sample for testing. Other reasons could be rare bacteria.
If you are having recurrent UTI a longer course of antibiotics is recommended.
We also need to rule out diabetes
. If you have another episode see a urologist
to rule out prostatitis
Hope this helps