Uti symptoms but no uti on culture is what?

It may never show up: Utis is a clinical diagnosis - that means for a physician, we rely mainly on the patient's symptoms (pain on urination, hesitancy, frequency, flank/supra pubic pain) to make a dx. In many cases, we can grow and isolate the offending organism in the lab in <24hrs.. In other cases, it is much harder to do this (eg chlamydia, ureaplasma, mycoplasma) - sometimes resulting in a negative culture.

Irritated bladder: Irritated bladder (interstitial cystitis) causes UTI like discomfort and symptoms in the absence of actual infection. It is usually caused by irritants such as caffeine, artificial food colors, sweeteners. Taking vitamin D3 10,000 IU/day, probiotics and zinc supplement (25-50 mg/day) may help resolve the symptoms since all of them help reduce inflammation and help the bladder lining heal up fast.