Mystery of Divine Healing

Several people whom I know have suffered tremendous pain and physical suffering over the course of many years. I and others have prayed hundreds of times for God to heal them. This has not happened. Last night another believer and I were discussing this phenomenon. What does the Bible say about healing, and how are we to understand our and others' experiences with this. One verse commonly used by proponents of modern day divine (miraculous) healing is Psalm 103:3 speaking of the Lord (v.2) "who forgives all your iniquity, who heals all your diseases..."
    Very quickly we run into a major controversy which has divided the Church. Are gifts of healing (and other gifts) as mentioned in 1 Corinthians 12:28 for a limited time period very early in the history of the so called primitive church (pre 100AD) or do these gifts extend until Christ returns? A key passage is 1 Corinthians 13:8-12. Verse 8 clearly states that the gifts will cease. It does not say when. Verse 9 refers to something called the "perfect" but is not clear what that is. Some understand this to be the completion of the canon of Scripture i.e. the New Testament as God has no further inspired revelation for us. How does verse 12 fit into this interpretation? It reads "Now we see in a mirror dimly, but then face to face. Now I know in part; then I shall know fully , even as I have been fully known." This seems to agree more with the understanding that the "perfect" is Jesus. When He returns we shall see Him face to face ( 1 John 3:2) and shall know as we have been known.
   So if the gift of healing exists why don't people get healed. One is that not everyone has every gift but those to whom the Spirit gives them. ( 1 Cor. 12:7.11) Two, if we do not believe in the possibility that a person can be healed then we are not walking in faith for the Holy Spirit to work in. Third is the understanding that ultimately God does things for His own glory, and we are not very good at giving Him that glory through our testimonies of what He has done for us. Fourth is the sovereignty of God. He does what He wills. Fifth, I do not know why.
   There are two mature men of God whom I respect greatly who both say that God has used them in miraculous healing, albeit in other countries. Perhaps there are clues there but for now it is still a mystery to me. I will continue to pray for people and hope for better results.