It may very well be in the way you breath, if you breath shallow, this will close off your lungs. You need to breath in deeply, and you will have to remind yourself repeatedly throughout the day. One cause of the rapid shallow breathing could be over masturbation. This will cause you to be fatigued and cause you to shallow breath, especially if you do it more than once per day. You are suffering from partial lung collapse, so just breath deeply, and when you spank it, don't pant, if you have to pant, you are doing it too frequently.