That could just be plain psychology. Studies found that when people watched others in pain, the part of their brain that registers pain went off. This probably goes far deeper. Laughter is contageous, sad movies make people cry, even yawns are contageous. We are mickers.
Empathy is when you don't know someone's emotions or pain and can still feel them. When you can sense energy through feeling. When you can profile someone's personality through feeling. And when you get "gut feelings" that are consistently correct and oddly precise in their nature. For instance, a thunderstorm began. I told the family member with me that there was going to be a fight, a big one and someone close to me was going to get hurt. But I couldn't figure out who in order to warn them. That night my aunt got into a fight with her boyfriend and he beat her severely.