As a child of God you will suffer one way or another. Some people have chronic pain. God knows what you are going though. Sometimes we ask Him why me? His answer is why not. Just because you belong to God doesn't mean your life is going to all be good. Actually you find it is a lot harder life as you have an enemy that tries to keep you away from doing what the Lord wants for you to do.
If you are in chronic pain think about the pain that Jesus went through to set you free and to be able to be with God. This might ease your pain.
There is someone who may be in more pain then you are. If you know this person pray for that person.