Urine swab generally refers to the urethral swab, the pain of urination after the examination is done may be caused by urethral mucosal injury, may also be caused by urethritis, urinary tract stones, and other causes such as cystitis. 1. Urethral mucosal injury: patients with urethral swabs may lead to cause urethral mucosal injury, patients do urethral swabs after the examination when peeing may stimulate the wound, causing painful urination. 2. Urethritis: Urethritis may be caused by gonococcus, chlamydia trachomatis, mycoplasma and other pathogen infections. Patients will have symptoms such as painful urination, frequent urination and itching in the urethra. If the patient has a urethritis in the urethral swab examination, urination will appear painful symptoms. 3. Urethral calculi: Urethral calculi are considered to be caused by heredity and taking medicines that can easily induce calculi. Patients will show difficulty in urination, dribbling urination, and pain in urination. When patients with urethral stones undergo urethral swab testing they will exhibit painful urination. Painful urination after a patient has a urethral swab test can also be caused by cystitis, ureteral stones, and so on. It is recommended that patients should seek medical treatment in time and choose the appropriate measures for treatment under the guidance of the doctor.