I went to my doctor a few months ago told her I have problems exercising with out my heart beating fast and making it difficult and painful to breathe. Now I notice a popping in the right side of my chest underneath my breast in between this little area that feels like a bone it feels like there s a lot of pressure in my chest that s almost really painful. What could this be my doctor says she doesn t think I have asthma and if I increase my exercise it will probably get better but I haven t told her about the popping noise and pressure in my chest yet.