This sounds silly, but today I was being given a piggy back ride and she was running very fast, when she abruptly stopped the centre of my chest right where my heart is and surrounding area was hit against her head pretty hard, I immediately felt a tightening and my heart beat became irregular, it hurt to move for a minute or so until I got up and brushed it off eventually after the pain subsided, that was maybe 11 hours ago now and as I have tried to settle down I am starting to experience a pain in my chest and shortness of breath and it is making me feel only how I can describe as strange, uncomfortable and somewhat frightened. what is this and should I be worried?