One of the main things to understand about healing is that God has already made the provision of healing available for everyone. God is not choosing who gets healed and who doesn't. Just like God is not choosing who gets saved and who doesn't. Salvation and healing are part of the same package (1Peter 2:24). If someone died and went to hell you can't say God didn't save him. God has made the provision of salvation for everyone, but the difference is some receive the provision and others don't. You can't say God didn't do it just because someone didn't get saved. Every sinner has salvation waiting on them to receive. Just like every sick person has healing waiting on them to receive. The one thing you can't do is look to your senses to tell you what God has done, because it don't know (1Corinthians 2:14). Let me give you an example in Luke 17 ten lepers cried out to Jesus to have mercy on them, in response Jesus said, "Go shew yourselves unto the priests." And as they went they were cleansed. Now when was the healing provided, when Jesus said, "Go shew yourselves unto the priest." That was all he did so whatever he did was done when he said. And as they went they received the healing that Jesus provided when he spoke.
Notice even though Jesus did what they asked of him their bodies showed no evidence of it. Your body can't tell you what God has already provided for you. Your body can only tell you when you have received what God has already provided. Some think that if God wants to heal then he will heal you, but that's not true. In 2Peter 3:9 it says, that God is not willing that any should perish, but that all should come to repentance. Let me ask you a question, does that mean no person will perish. Notice his will has nothing to do with whether anyone will be saved or not, but because it's his will he made the provision of salvation for everyone to receive. I've said it once and I will continue to say it, God wants you healed. How can I say that, because he made the provision for you to receive. Why would he provide something that he doesn't want you to have. Notice why Jesus came, to destroy the works of the devil(1John 3:8) and for you to have life and have it more abundantly(John 10:10). Now we know from scripture that sickness is a work of the devil (Acts 10:38). In other words the devil is the root cause of sickness. Sickness is the result of sin and sin came into the earth when man listened to Satan instead of God. So Satan became man's God (2Corinthians 4:4). And as a result his nature and the results of his nature was loosed in the earth. But, Jesus came to destroy the works of the devil. And on the cross Jesus said, "It is finished." Healing is complete just like salvation is complete. And you receive both of them by faith.
Now let's look at the word salvation because a lot of people hear that word and just think of being born again, but it means far more than that. Salvation means in the greek(heal, deliver, preserve, protect, make whole). Check your concordance for youself. And Romans 10:10 shows you how to receive salvation. You receive by faith in your heart and by the confession of your mouth. Notice it says with the mouth confession is made unto salvation, but I can't confess unto something that hasn't already been done. Because it is done is why I can confess it. This is another key to receiving healing, what you say is very important. The scriptures even tells you that your words are health(medicine) to your flesh (Proverbs 12:18; 16:24). James 3 tell you that if you can control your tongue then you can control your body. Notice in 1Peter 3:10 it says, if you want to see good keep your tongue from speaking evil. That's a principle so you could say if you want to see healing keep your tongue from speaking sickness. So, what you speak is very important to you receiving your healing. It's important that you speak in line with what God has said, by his stripes I am healed. And be patient, give it some time. Because the scripture says it is impossible for God to lie. So those things are very key to receiving healing: First God has already provided healing and wants you to have it. Second it's received by faith just as salvation for being born again. And Third what you say is very important to what you receive.