I've interstitial cystitis. It has gotten worse with searing pain. Urinalysis revealed elevated nitrates, but no bacteria grew. What could this be?

Treat bladder. Nitites are a sign of infection, i would treat despite the culture. I place patients an a seratonin norepinephrine reuptake inhibitor, like cymbalta, (duloxetine) to help with ascending pain signals. It works well but nitrites mean u likely have n infection, cultures can be wrong. Look it up and inform the doc.