Sickness is part of this life. Sometimes because of our own mistreatment of our bodies, sometimes, because of our environment and sometimes just because the body fails to work like it was supposed to.
There has been great advancements in medicine and God can use that to heal you. God can also supernaturally. God is the great healer and it should always be the first thing we do when we get sick. Lifted up to the lord first. The Bible tells us to pray for whatever we need, and that surely includes freedom from sickness and pain.
Sometimes healing does not occur, even to the most loving, God-centered people. Why not? We don’t really know, however, the Bible does promise us that if we are not healed in this life, there is something greater awaiting us afterward.
Heal me, O LORD, and I shall be healed; Save me, and I shall be saved, For You are my praise. Jeremiah 17:14 (NKJV)
For I will restore health to you And heal you of your wounds,' says the LORD, 'Because they called you an outcast saying: "This is Zion; No one seeks her." ' Jeremiah 30:17 (NKJV)
And when He had called His twelve disciples to Him, He gave them power o ver unclean spirits, to cast them out, and to heal all kinds of sickness and all kinds of disease. Matthew 10:1 (NKJV)
And there are diversities of activities, but it is the same God who works all in all. But the manifestation of the Spirit is given to each one for the profit of all: for to one is given the word of wisdom through the Spirit, to another the word of knowledge through the same Spirit, to another faith by the same Spirit, to another gifts of healings by the same Spirit, to another the working of miracles, to another prophecy, to another discerning of spirits, to another different kinds of tongues, to another the interpretation of tongues. But one and the same Spirit works all these things, distributing to each one individually as He wills. 1 Corinthians 12:6-11 (NKJV)
Now you are the body of Christ, and members individually. And God has appointed these in the church: first apostles, second prophets, third teachers, after that miracles, then gifts of healings, helps, administrations, varieties of tongues. 1 Corinthians 12:27-28 (NKJV)
Concerning this thing I pleaded with the Lord three times that it might depart from me. And He said to me, "My grace is sufficient for you, for My strength is made perfect in weakness." Therefore most gladly I will rather boast in my infirmities, that the power of Christ may rest upon me. Therefore I take pleasure in infirmities, in reproaches, in needs, in persecutions, in distresses, for Christ's sake. For when I am weak, then I am strong. 2 Corinthians 12:8-10 (NKJV)
For we know that if our earthly house, this tent, is destroyed, we have a building from God, a house not made with hands, eternal in the heavens. For in this we groan, earnestly desiring to be clothed with our habitation which is from heaven, if indeed, having been clothed, we shall not be found naked. For we who are in this tent groan, being burdened, not because we want to be unclothed, but further clothed, that mortality may be swallowed up by life. 2 Corinthians 5:1-4 (NKJV)
Therefore we do not lose heart. Even though our outward man is perishing, yet the inward man is being renewed day by day. 2 Corinthians 4:16 (NKJV)