hi, thank-you for providing the brief history. As you have intercostal muscle spasm this will last for about a week or two. As there will be inflammation of the muscles and may be costochindritis this pain will last a maximum of 2 weeks. I will advice you to undergo some simple breathing exercises like - 1. Deep breathing exercises 2. Diaphragmatic breathing exercises 3. costal breathing exercises 4. pursed lip breathing exercises 5. abdominal breathing exercises. As doing this breathing exercises will help improve the strength of the muscles of respiration and improve the lung capacities as well. Kindly note that when performing this exercises you Need place the hand on the injured area so the pain will be avoided. Regards Jay Indravadan Patel