We lets see if i can help. Take our sun for example, it's much bigger than we are, so big we're orbiting around it. Now if we had a star half it's size, we might fly off into space. Likewise, if it were larger we'd get pulled in. this is due to how much "distortion" the star has in space, i.e. gravity.
What Einstein basically is saying with E=MC2 is that the more gravity an object has, the more it affects things around it.