Hi I have strange thing happening to me recently. This makes me very anxious. It is a feeling like something rubbing inside my chest on the heart side or else words like someone would knock on the top of my sternum, or even higher, closer to clavicles? Is it very dangerous? I m 23 years old, female, 61 kg weight, 180 cm tall. Generally I m a very nervous person. Very easily getting stressed or over excited. But while I had a visit to cardiologist he said my heart is generally healthy but part of mitral valve is not closing fully (but as he explained it is very common to young girls and women and I shouldn t worry, he did some tests and this is all). Is this what I experience now something dangerous? Thanks...hAnna