To be absent from the body is to be present with the Lord.....I forget the Scripture but there you have it....Once your body dies your spirit leaves and you are present with the Lord.......But does one have to die before going to Heaven.....I say no....many will not die an earthly death when Christ comes to Rapture the church....But I feel all must die a spiritual death as Paul so often mentioned...We die to ourselves as Paul writes....I died.....I no longer live...But Christ lives in me....As long as we are living for ourselves Christ is of no affect in our lives....So Paul was saying He died when Christ died on the cross....He identifyed himself with Jesus on the cross....Now Paul lives by giving his life to Jesus.......Jesus now has full rein in his life......and all his writings showed that.
I hope this helps............................