I have been recently having mucus run down the back of my throat and it feels like a constant lump in chest and throat area (I am breathing perfectly well though.) I don't feel bad, no fever, no NOTHING! Along with this though, I have been experiencing this weird thing with my heart that is very hard to describe and every time it happens I let out a small cough. It tends to happen when I'm laying down or sitting down but not while I'm standing. I really don't know what to do and need some help with figuring this out. P.S. I am a 16 year old female with a family history of breast cancer and diabetes also high blood pressure.