It's normal to feel TESTICULAR discomfort after sit-ups.. It's due to increased intra-abdominal pressure.. The pain should go away in a few hours. If it persists, apply an ice pack on the area for 20 minutes.. Take over-the-counter pain relievers, if the pain is severe.. If you notice swelling or REDNESS, seek medical attention.. Remember to breathe out during the sit-up's exertion phase.. Avoid holding your breath.