The more a man sins, the more pain he experiences. Death feels worse the more he has sinned in this life.

The sting of death is sin; and the strength of sin is the law. 1 Corinthians 15:56 KJV

Death is not the sting. Sin is the sting. If a man turns away from sin and follows Jesus, he will not sin as long as he is living according to the will of God and the teachings of Jesus. It is the law that gives sin its strength to hurt. The Lord helps us keep his law when we ask him. His main commandment is:

Love one another.

We are not alone when we battle against sin. Jesus gives us the victory. It is our duty to receive the strength of his spirit. And his spirit is love. When we allow love to flow through us to others, we are not sinning.

But thanks be to God, which giveth us the victory through our Lord Jesus Christ. 1 Corinthians 15:57 KJV

When we follow Jesus and ask for his help to overcome the sin nature of our flesh, he gives us the power to triumph over it. Our victory is through Jesus, not through our own effort alone. And if we are not sinning, then death has lost its sting. For someone walking in the spirit and not in the flesh, the death of the physical body should be ecstasy, or at least painless and peaceful.