c'est normal, c'est du PCS (Precordial Catch Syndrome)
PCS manifests itself as a very intense, sharp pain, typically at the left side of the chest, generally in the cartilage between the bones of the sternum and rib cage, which is worse when taking breaths. Patients often think that they are having a heart attack which causes them to panic. This pain typically lasts from 30 seconds to a few minutes.