Added this bit to https://painimprovement.com/painful-urination-or-bladder/

If you have a painful bladder, or burning and/or frequent urination, (need to urinate often), or have lower abdominal or pelvic pains, or have been diagnosed often with bladder infections only to find out from your doctor a few days or weeks later that it was not a bacterial infection, you may have Interstitial Cystitis.

Infection causes inflammation. There are other causes of inflammation, including injury, connective tissue disease, and even anxiety and PTSD cause inflammation. Inflammation can even cause blood in the urine. See your health care provider for this.