question: I have uncomfortable chest feeling after I walk/run or speak for a long time, it feels like I am running out of breath but I show know signs of it. I tried a pulse oximeter and its always between 95-95%. When I hold my breath it seems like I cant hold a lot of air for a long time like I used to be able to. I have no prior heart issues (other then mitral valve prolapse) and not family history of heart issues. I feel like its coming from my lungs the uncomfortable feeling. It is not a sharp pain. It does make me feel like I am low in breath. After I hold my breath for a while I feel the uncomfortable feeling in my chest. Any ideas?