Penile swelling and pain may be caused by foreskin ingrown, trauma, urethral stone and urethritis. 1. Circumcision ingrown: usually leads to obstruction of venous return to the penis and distal glans, resulting in symptoms of penile swelling and pain. 2. Trauma: for example, injury to the corpus cavernosum of the penis or prolonged friction can cause edema of the corpus cavernosum of the penis, and this condition can easily lead to penile swelling and pain. 3. Urethral calculi: it can cause persistent penile distension and pain, and accompanied by symptoms such as hematuria, difficulty in urination, divergent urination or complete inability to urinate. 4. Urethritis: when the patient suffers from gonorrhea urethritis, the infectious pathogens stimulate the urethral mucosa, which leads to penile distension. Patients with symptoms of penile distension, should go to the hospital in a timely manner, under the guidance of the doctor to clarify the cause of the disease, and targeted treatment.