But let's not get diverted into a discussion of the cruelties of modern slavery. The most puzzling aspect of God's behavior toward Mankind is that He hamstrung Himself by granting us free will. This does not restrict God's Sovereignty, of course, but it allows Sin to be a sifting point of our behavior and spiritual development, the wat that I see it. Pain is not bad, it's good, as I explained to Bill Tarver, for it warms us that damage is occuring. Neither I nor the object of my attitude or actions will be immune from any potential pain, disease, or destruction.
Bad things happen.
God has promised the Judgement will make all things right. This Life is our test, our chance to grow. No doubt you can dream up a bible quote to substantiate that. Pain receptors were part of the Design, for reasons of self-protection. The introduction of Disease gave a whole additional dimension to the function of pain receptors, the way that I see it.