Sometimes, when I sit, I feel like there s sudden beating between and below my lungs, somewhere in diaphragm I guess, it s not hurt or anything, it s only beating like a heart, but only once or twice per day. It has never happened before. And it starts last week. Is it normal, and what is that beating feeling exactly, and where it takes place actually, because I m not sure either, whether it s spleen or diaphragm