Fi combined with Ni feels like being on a journey or in a trance. Time moves slowly, and you just stare into a fixed point in space, feeling whatever you're feeling, ignoring your sorroundings while somehow being conscious of them.
I'm 30 now, and it's only been in the last year that I've actually noticed that my emotions have a physical feeling as well (beyond the customary "lump in the throat" and "mouth dry with fear" stuff). I was ridiculously out of touch with this prior. And I seem to be Fi-dom.
I definitely know the feeling of "heartache" though. That's another one I've always noticed--I get a sharp stabbing sensation in my left breast when I despair. It physically hurts.