Can you be in the middle of hell and heaven?

No, not literally. You are here on earth, an actual place where you are living your life. There is scientific proof that earth exists, and proof that the human beings who live on earth also exist. But heaven and hell are part of a religious belief system, and neither can be proved-- they can only be believed, and they exist in the world of faith.

Sometimes people will say they feel they are trapped between heaven and hell, and they use that metaphor to describe a situation that has moments of great happiness (heaven) and moments that are horribly painful (hell). And yes, some very religious people do see life on earth as a preparation for either heaven (if you do good) or hell (if you do evil).