I have heard many, perhaps hundreds of testimonies of people who have been healed through the demonstration of the Spirit of the Lord. And many on the other end, who have prayed, like Paul, for a healing (spiritual or physical), and found the Lord saying... my grace is sufficient for thee.
So we have to understand that God is all in all. He has the ultimate supreme right and ability to decide when, where and how His healing mercies will flow.
Why did Jesus not heal Paul of his "thorn in the flesh"? Because it was given to him that he should not glorify in his own accomplishments above measure. It was something given to him by the Lord to keep him humble.
I've heard many people tell of being healed of one thing or another, but that they still suffered from a certain ailment that never could be completely removed from them, and they believe the Lord left it there for a reason and for a purpose. Who are we to question the mind of Jesus?
I do believe that we can trust in the Lord for our healing both spiritual, and physical. He is the Great Physician. Doctors are just men trying to "practice medicine". They continue to learn, and understand the human body and all its intricacies. But only Jesus, our Great Physician completely understands and knows all these things. Jesus is not practicing medicine, He IS the physician.
That being said, we must be led by the Spirit in ALL things. If we pray for healing, and we have not found it, if we have sought it carefully with all faith, and have cleansed our hearts of any unforgiveness or hidden sins, and have done all on our end we can do, then we must rest in Jesus and continue to trust him. For one thing we know, is that unless the resurrection takes place while we are still alive, the other alternative is that our bodies will die a death from an illness, injury or accident.
I believe healing is indeed an intricate, necessary and absolute part of the gospel message. However, if a healing does not take place, then one must continue to worship Jesus, and praise Him, and when He so desires, there may come a time that unexpectedly we receive our healing.
We cannot order the Lord around and expect Him to do things at our beck and call. All things must be done asking for His perfect will. Yet, we can have faith and believe - even for those who have no faith. The gospel message does include healing as well as salvation. But we have to understand that Jesus holds the ultimate keys, and it is in Him that we must trust completely to have the final say in all things.
Just some of my thoughts. I guess we are all entitled to our opinions on this matter