A: God’s desire for the Christian is ultimate healing. Revelation 22:2 says, “Through the middle of the street of the city; also, on either side of the river, the tree of life with its twelve kinds of fruit, yielding its fruit each month. The leaves of the tree were for the healing of the nations.” This is one of the last activities we see of God in Scripture, and it refers to the reality of the New Heavens and the New Earth that will come down after the Last Judgment at the return of Christ. God will usually heal a sickness on the earth in the fallen world one way or another, but not always. Everyone gets sick sometimes. Almost everyone recovers.
God has given the body ways to heal itself, he has given us doctors and medicine, and he has given us the Holy Spirit and people of faith to pray for healing. In this world where the Kingdom of God has not fully come, sometimes healing is delayed. But because of Christ, everyone on the New Earth will be healed. Don’t stop praying for healing in this life, but know with certainty that the next life will bring perfection and healing.
God’s plan for the Christian is that one day there will be no pain, no weeping, only health and joy. If he makes you wait for that great day, then he has a purpose in it. It doesn’t change the fact that sickness and disease is demonic, but God will do away with satan and demons in that great day. It is his promise (Rev 20:10). And he will do away with their evil works on the same day.