First of all..it IS God's will to heal, just like it is that GOD 'would have NONE perish". When we pray "Thy will be done on earth as it is in heaven..."....take a serious look at what you are saying. You are asking GOD that what is going on in heaven in accordance to HIS will to be applied to this earth that you are wandering around on for the moment until you get to heaven. Take a look at heaven. Are people walking around with headaches, diseases, crutches and needing medical attention? The answer is obvious. I believe it is always HIS will to heal, save, sanctify and much more. However, us earthlings have issues with His timing. IT took some people in the BIBLE to be healed after 12 years of spending all their monies on doctors and cures, Some people were crippled for 40 yrs or more. We do not know the time involved for those 10 lepers to reach the point where they were cured instantly. Some 'healings" do occur immediately, some take a little time, such as when the blind man told JESUS 'I see people walking as trees" and then JESUS touched the man again. Some healings take a leap of faith, such as when Naaman had to dunk himself into the Jordan River 7 times before his leprosy was taken away. I recal that Smith Wigglesworth, who was one of the greatest 20th century 'healers" had a deaf daughter who lived her entire life as a mute. But, she's healed NOW. I also like how JESUS did not preselect those in whom He healed..."all were healed"..meaning, not just a certain culture, race, creed, Christ follower or not. When a person totally surrenders themselves to Christ, we are healed of our past sins, our present sins, and our future sins by the power of the blood of JESUS. We are to seek and to save that which is lost, baptising them, healing them, casting out demons...etc. All were part of the 1st century newly formed 'church". Signs and wonders always followed, such as Philip, who was NOT part of the original Apostle lineup. I personally, have actually touched a part of my body that was hurting and diligently prayed and on two or more occasions, was instantly touched by the Holy Spirit and healed. This included gout, a spinal condition, and severe sinus infection. My grandfather would lay his hands on me and others and they would be healed either instantly or by the next day, and he was just a Southern Cotton Mill worker. I do know that JESUS said "Thy faith hath made thee whole...." I also know of an evangelist who was born with NO legs or arms and this very day, is a proud father, a word renown minister who can and will be totally healed...either now or later. To me, it's all in GOD's timing....for HIS will is always in our favor! I mean, look at what GOD had to sacrifice for us. Doesn't that tell us that our healings, mentally, emotionally and physically were so important to HIM that earth got to meet HIs very Son, in the flesh. We today can have the same pleasure in the Holy Spirit, our Comforter. Keep in mind also....the faith of a few good friends has healing powers. GOd also inhabits our praises. If we live each day with praise, no matter the pain....HE is sure to bend an ear and use us mightily. John, the Apostle, survived not one, but TWO dunkings in hot oil that would have normally killed him instantly. I do believe that modern healings and miracles still occur because GOD is the same yesterday, today and tomorrow. I would also encourage you to read anything about John G. Lake, who had several healing centers scattered across the U.S.A for decades until his death in 1935.