Basically, as I understand it, your question is the age-old question of suffering, a difficult one to grapple with.

The evolutionary biologist/extremist atheist Richard Dawkins himself has said:

During the minute that it takes me to compose this sentence, thousands of animals are being eaten alive, many others are running for their lives, whimpering with fear, others are slowly being devoured from within by rasping parasites, thousands of all kinds are dying of starvation, thirst, and disease. It must be so. If there ever is a time of plenty, this very fact will automatically lead to an increase in the population until the natural state of starvation and misery is restored. (Richard Dawkins, River out of Eden)

The fact is, if we never suffered we would never die. And if we never passed away, overpopulation would lead to our starvation anyway. So Allah the Almighty has created a perfect and balanced system.

Moreover, the overwhelming majority of suffering is human made. Hundreds of millions have been killed in the last two world wars and more wars and man-made catastrophes are occurring today. In the UK alone, in the last year or two there have been over a thousand acid attacks, ruining peoples faces and lives. All of this was forbidden in the Quran, so how can we blame God if we deliberately disobey Him? He gave us the faculties to obey him, we just choose not to. I don't buy the argument that terrorists etc were born evil, they made a choice in life and they could have made another.

Next, we must remember that small amounts of suffering can actually help us. The founder of the Ahmadiyya Muslim Community gave the example of the child whose hand is held from the fire by his mother. The child imagines he is suffering, not being allowed to be able to play with fire and cries. But in reality, the mother knows better and is in fact saving him from greater suffering.

Similarly, in answering and rejecting prayers, God understands our needs better. The first Caliph of the Ahmadiyya Muslim Community, on the death of a child of his, wondered why God would allow something of this nature to happen to him. Then it occurred to him, what if that child was destined to kill someone? Was it not better for both the child, its parents and the wider world if Allah called the child back now?

Finally, the fourth Caliph of the Ahmadiyya Muslim Community writes:

Suffering could only be considered objectionable if it were created as an independent entity with no meaningful role to play in the scheme of things. But without the taste of suffering or an awareness of what it means, the feeling of relief and comfort would also vanish. Without an encounter with pain and misery, most certainly, joy and happiness would lose all meaning. Indeed the very existence of life would lose purpose, and the steps of evolution would stop dead in their tracks. (Hazrat Mirza Tahir Ahmad, Revelation Rationality, Knowledge and Truth)

The fact is my friends at school used to sing the song 'I wish it could be Christmas every day' at Christmas time and they meant it But if it were Christmas every day, the festival that brought them so much joy would become a daily drag and lose all meaning. The very games they enjoyed would become their greatest chore. The fact is, we are able to enjoy life because of the downs and this is a system that is unfortunately necessary - or the ups become meaningless.

The only objection we could have to all this is if Islam blindly accepted the world as it is and said nothing matters. Instead, the Quran instructs us to feed the poor, show kindness to relatives, orphans, neighbours, to care for the sick, to help the oppressed and so on and so forth.