Either possibility is plausible. Not all the cultures are able to grow out bacteria - it is possible to have a culture-negative UTI. I would assume that appropriate antibiotics were given to treat this.
If the symptoms continue, you can consider metabolic causes like diabetes or thyroid disorders.
Infection can be checked again. If negative, you can consider a urology referral for possible urodynamic studies.
These options can be discussed with your personal physician.
Followup with your personal physician is essential.
This answer is not intended as and does not substitute for medical advice - the information presented is for patient education only. Please see your personal physician for further evaluation of your individual case.
Kevin, M.D.
kevinmd_b