Why does God allow pain and suffering?
God didn't start it; humanity did. God made humans the stewards over creation at the very beginning and gave them one prohibition: "but of the tree of the knowledge of good and evil you shall not eat, for in the day that you eat of it you shall surely die." [Gen. 2.15-17 ESV]
The knowledge of good was experienced through intimacy, walking with God in the Garden. The knowledge and experience of evil was unknown until Adam and Eve disobeyed God and allowed Satan to remain in the Garden. Stewardship includes protection. Their disobedience led to the abdication of their stewardship and handing it over to Satan. Satan's stewardship of the earth, brought hate, depression, illness, war, disease and death. The first humans allowed it to happen; effectively they gave Satan permission to act in their place. With the knowledge of evil comes the experience of evil. The experience of evil includes sin, sickness and death. But the experience of evil was not God's plan.
Does God allow pain and suffering? Yes, in the sense that He gave Adam and Eve the freedom to both prevent suffering and the freedom to allow it, and they chose to allow it. They allowed it by following Satan's suggestion rather than adhering to God's warning. We humans blame God for what humanity allowed; what He prohibited. Then we have the audacity to blame Him for the decision our human family made.
We ask "Why does God allow all of this suffering?" as if we had nothing to do with it. As if we never participate in evil as did our first parents. We want the ability to choose for ourselves but we don't want to be held responsible for our decisions. We want the freedom to love and to be loved but we talk like we don't want the freedom to reject love, even though we frequently reject love and chose selfishness. We want to be independent and free but we don't want a Hitler to be free and independent. This feels acceptable to us because we do not honestly evaluate the hypocrisy of our own desires. We conveniently ignore our own inconsistencies and selfish desires, while pointing out other's errors and blaming God for it. This attitude also feels acceptable to us because we have such a warped view of righteousness; we don't really consider what holiness is. Our convenient view of righteousness is that if we can find someone, anyone who seems worse than us, then we declare ourselves "holy". As if we are God and get to write the definition of good and bad. And why not? Wouldn't we make that same decision at the very beginning? Isn't ok to eat from the tree of the knowledge of good and evil if I want to - especially if it makes me happy?
But God has shown us that real righteousness and true holiness do not include any amount of wrongdoing or wrong thinking. In reality, we do not have permission to rewrite the definitions of holiness and righteousness. Paul, an early follower of Christ, observed "All have sinned and fall short of the glory of God." [Romans 3.23]
Please do not misunderstand me. I am not suggesting that you are suffering with an illness because God is punishing you for a specific sin that you committed. Rather, I am saying that all of us are suffering due to the sin that has infected humanity since the fault of our first parents at the dawn of time.
Even so, God has guaranteed our escape from pain and suffering. Through the Son of God, the man Jesus, our escape from pain and suffering is guaranteed. [Romans 5] This life of pain and suffering is temporary, but the next life is free from all of that. Jesus invites us to make Him the steward of our lives and so be free from the control of Satan. God does care about our pain and suffering and wants us to be free from it more than even we do. God desires our freedom to such an extent that He sent His Son Jesus to bear the penalty for our rebellion and to destroy the outcome of death. [1 Peter 3.18-22]
At this time we still experience pain and suffering, but if we put our faith in Jesus and follow Him we will not continue to live in pain and suffering for ever. God will not allow any amount of sadness, illness or suffering to follow us into His presence, and He will exact perfect justice. [Revelation 21.3-8] This is why Jesus said, "The thief [Satan] comes only to steal and kill and destroy. I came that they [us] may have life and have it abundantly." [John 10.10]
The solution to pain and suffering is following Jesus. [John 3.16]