As a figure of speech, yes, Heaven does exist. But it doesn't exist in the physical world. The word Heaven is used to described very wonderful things. When you hear people say they are going to heaven after they die, they aren't talking about a physical location. They are talking about their soul going to a non-physical place called Heaven. I can see how many people misinterpret this, as it is said in such a way that portrays Heaven to be a physical place.
The bible speaks of heaven as God's throne and earth as His footstool, so although we may be in agreement that heaven is not physical, it certainly is tangible and according to Jesus' words in
Luke 17:20-21, it does indicate that those born of the spirit are citizens of heaven even while enduring their physical life. However the physical life ends and God tells us in many ways that our spiritual life never ends, that's the whole purpose of life really isn't it? That God gathers the wheat into His barn and burns the weeds. Why does God want to gather wheat into His barn? That's something that we just don't know but we choose to trust that He has good intentions
Knowing what I know of Jesus' character there is certainly no other King I would choose to serve.
This is pertinent:
1 Corinthians 15
The Resurrection Body
35 But someone may ask, How will the dead be raised? What kind of bodies will they have? 36 What a foolish question! When you put a seed into the ground, it doesnt grow into a plant unless it dies first. 37 And what you put in the ground is not the plant that will grow, but only a bare seed of wheat or whatever you are planting.
[...]
44 They are buried as natural human bodies, but they will be raised as spiritual bodies. For just as there are natural bodies, there are also spiritual bodies. 45 The Scriptures tell us, The first man, Adam, became a living person.[h] But the last Adamthat is, Christis a life-giving Spirit. 46 What comes first is the natural body, then the spiritual body comes later. 47 Adam, the first man, was made from the dust of the earth, while Christ, the second man, came from heaven. 48 Earthly people are like the earthly man, and heavenly people are like the heavenly man. 49 Just as we are now like the earthly man, we will someday be like
the heavenly man.