I've had periodic bladder spasms for yrs w/o infection. been to uros, gyn, found nothing. should i worry or just treat w/ azo or such when it happens?

Painful bladder: If you have a variable degree of increased urinary frequency associated with bladder or pelvic discomfort and no uti, you may have a condition called interstitial cystitis/painful bladder syndrome which is commonly either under- or mis-diagnosed. Diagnosis made on basis of symptoms, normal urinalysis and imaging and a cystoscopy/hydrodistension of bladder under anesthesia (not in office).

OAB: Is not uncommon to have a negative examination and tests with these symptoms. As long as nothing physically wrong is found, and is not frequent , you can treat it symptomatically.