Hello, You fell and after that you have been experiencing pain under the right breast & armpit. You have also developed a popping sound. it is sore and you can t sleep on that side. Popping sound with pain, swelling, and a tightening in the chest may require medical attention. Your symptoms are suggestive of slipping rib syndrome. Chest popping occurs commonly after a hard fall or direct blow to the chest region. When the cartilage attached to any of your “false ribs” breaks, it results in abnormal movement and popping sound. It s this slipping out of normal position that causes pain that s felt in your upper abdomen or lower chest. You are suggested to get clinically examined by a GP. Get required blood tests and imaging tests (X-ray, CT/MRI) done so that treatment can be started at the earliest. In the meantime, taking Nonsteroidal anti-inflammatory drugs, Naproxen or Combiflam, one stat after food when pain can help relieve soreness, inflammation, discomfort and pain. Physical therapy may be helpful. The treating doctor can consider giving intercostal nerve injections, to ease pain and inflammation in case of severe pain. Osteopathic manipulative treatment or surgery may be recommended depending on the response of treatment. You are suggested to be at rest. Get treated at the earliest. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Nupur K., General & Family Physician