Not just figuratively, but literally as well. In Sil Num Tao the punch comes from the heart and goes out from there. The chain punch is the main strike of the Ving Tsun (aka wing chun) system, it is a very effective punch. The technique takes some practice, but with some time and attention you can master it fairly quickly.
Another meaning behind the saying "the punch comes from the heart" is intention. Anything worth doing should done with intention, especially if you are throwing a punch. But it is just as important with anything else you do.