Then how can he have come down from heaven, he, himself?
Read John chapter 6
25"Though I have been speaking figuratively, a time is coming when I will no longer use this kind of language but will tell you plainly about my Father. 26In that day you will ask in my name. I am not saying that I will ask the Father on your behalf. 27No, the Father himself loves you because you have loved me and have believed that I came from God. 28I came from the Father and entered the world; now I am leaving the world and going back to the Father."
No one has seen the Father except the one who is from God; only he has seen the Father.
Jesus knew that the Father had put all things under his power, and that he had come from God and was returning to God;
Jesus said to them, "If God were your Father, you would love me, for I came from God and now am here. I have not come on my own; but he sent me.
No one has ever gone into heaven except the one who came from heaven—the Son of Man.
For I have come down from heaven not to do my will but to do the will of him who sent me.
So obviously, and clearly, Jesus Christ existed in heaven, as God (Came from God, and Returned to God) and came down to earth.
Lastly, Jesus was in the physical presence (definition of presence is physical proximity) to the Father since all eternity.
John 17:5 And now, Father, glorify me in your presence with the glory I had with you before the world began.