I read a good book awhile back - "Healed without Scars". It was all about how we keep trying - in our own way - to heal our old wounds. We keep pulling the scab off. Everyone knows that pulling the scab off, will make it scar worse.
Reading the book, I came to realize something that I was doing - in my friendships - that came from old wounds. Without realizing it, I was repeating an old scenario, trying to make it turn out different, unconsciously trying to heal a wound left from my childhood, which was messed up by an alcoholic father, and a bi-polar mother, and severe bullying at a "church school".
The book explained that Christ is the ONLY HEALER. Only HE can heal those old wounds. No amount of trying on our part will bring healing. We cannot heal ourselves.
I throw this in to the discussion, because I was a sincere believer for 25 years BEFORE I read that book. It still took several years, for me to consciously amend some negative interpersonal habits. It's just that the book opened my eyes to the source of those behaviors, which seemed beyond my control.
Those of us who have suffered - from whatever cause - can serve to help others. The author of the book had been abused. I know this does not answer the question concerning why God ALLOWS the suffering.
I personally have suffered from chronic migraines for 45 years. I was also born with Chiari I malformation. I've never had a C1 vertebra, and after decompression surgery the posterior process of C2 is also gone. My neck is somewhat unstable, and is now showing a lot of degenerative changes. (I'm turning 69 on Friday.) And yes - it is painful. So I think I can honestly say that I have suffered both physically and emotionally. [Though nothing like being burned over 50%. Wow!!]
I can also say - without any doubt, that God exists. I have personally experienced many - couldn't be anything else but - miracles. The first of those miracles absolutely CHANGED me. When you KNOW - absolutely - that God exists, you do start to think in different terms. And as I began to ask HIM questions, of course - the question concerning all the PAIN came up rather quickly.
The clearest thing I can tell you, is that the pain does have a purpose. The pain is like awful chemo, or painful surgery to kill cancer. Yes - it is very painful. But it is necessary for a good outcome. And Jesus knows that He can heal our hearts and minds, as well as give us new immortal spiritual bodies. [I'm speaking of pain in general, being necessary for the universe of God to experience.]
When we are living in the earth made new, a hundred thousand years from now, let's say that I wonder why I have to follow a certain Law of God. I start wondering. I will immediately know why! Because I have FELT the pain that doing things without God, or in opposition to God, brings. I know what sin cost Jesus and the Father. The cross was only a revelation of the pain that God feels, as He experiences our pain. He feels our pain - with us. He would have to be infinite, to survive, absorbing all that pain.