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.