Urinary urgency. what causes it if no infection found?

Urinary frequency: Any irritation or obstruction can cause urinary frequency - there doesn't need to be an infection per se. A UTI is the most common cause and can usually be identified by urinalysis. An "overactive bladder is a common diagnosis, but retention of urine is often another common cause. Neurologic irritation can cause frequent voiding and interstitial cystitis/bladder ca, too. Needs to be ruled out.

OAB, IC, stone etc.: Overactive bladder, interstitial cystitis, bladder stone, menopause in women and enlarged prostate in men can all cause urinary urgency. Start by cutting out acid urine producing foods and beverages like oj, caffeine, spicy foods and alcohol for a week or so. Resume above, if necessary, one at a time and consult your dr.

Pelvic Joint Injury: Frequency and urgency can be caused by an infection which doctors can detect.  often  a burning sensation accompanies infection & during urine flow.  other causes are theorized to come from relaxed and stretched pelvic floor muscles.  to my mind irritation of the pelvic neural plexsus by an underlying hypermobile sacroiliac joint is causal, as i explain at quora.Com.