Ah, like the old expression, it only hurts when I laugh. When you laugh, there is much air passing through your diaphram - your lungs and will cause them to swell as well the muscles are expanded. I once was with a friend, we were making jokes all nite, and the next morning, we both woke up with horrible pain from having laughed so hard. A hearty laugh is also good for you, and believe it or not, great exercise
