If God is loving, just and merciful why does He allow pain and injustice when He has the power to remove it?

Should a teacher do the sums for a child? Could an aspiring craftsman learn his trade if the tedious arduous work was done by someone else? We are here to learn, to develop and progress, so we must be allowed freedom to make mistakes, to choose this or that road and if, having been grated freewill, we make wrong decisions, will we not learn better when we suffer the consequences? One of the laws of life is that effect follows cause and everything has its consequence. If this law is part of our curriculum on earth why should there be divine intervention to alter it? Even illness and pain can be the result of wrong decisions. The uncertainties and vicissitudes of life do not in any way contradict the concept of the universal sovereignty and beneficence of God. All evolutionary creature life is beset by certain inevitabilities. To acquire strength of character man must be reared in an environment which necessitates grappling with hardships and reacting to disappointments. To realise the satisfaction of happiness he has to live in a world where The alternative of pain and the likelihood of suffering are ever present possibilities.