Hi, Overactive bladder and Interstitial Cystitis (IC) are two common disorders in the family of hypersensitivity disorders of the bladder. Both can cause urinary urgency and frequency. Overactive bladder is not asssociated with bladder pain, however IC is usually associated with pain, pressure or discomfort in the bladder, usually worse with a full bladder. Your symptoms of "pressure and irritation" make IC more likely. IC also shows a distinct hypersensitivity to foods and fluids that irritate the bladder like caffeine, alcohol, and acidic fruits and beverages. Symptoms of IC can flare up, and resolve spontaneously. If you have a flare up of symptoms, and a urine culture is negative for infection, you may have IC. You need to see a Urologist or Gynecologist who specializes in pelvic pain for a correct diagnosis and treatment. Go to the website of the Interstitial Cystitis Association: "ichelp.org" for more info. Good Luck