Starts with urinary infection 3 months back .now the irritaion continues and culture blood test aswell as scan shows normal study.

See below: This sounds like it could be interstitial cystitis, or painful bladder syndrome; this requires a thorough history and physical by a doctor, ruling out of infections with ua and culture (which sounds like it has been done), and if compatible, a potassium sensitivity test. Cystoscopy may also be needed to rule out other causes. Arrange for a referral to a urologist.