One passage stands out: Your eyes saw my unformed body, and on Your book they were all written; days have been formed and one of them is His. (Psalms 139:16). It would seem this would put an end to the debate over whether a human being's life is random, or whether it is "planned out" in advance.
However, it can lead to further debate-- those who insist it means human beings do not have free will at all, and those who insist it means tragedy and suffering must be "God's will."
Neither of these arguments are accurate. While not intending to be flip, one can look at it like a movie one has seen before: you may know everything that is going to happen, and you may know how it is going to end-- but knowing it does not mean orchestrating the actions of the characters or the settings. Similarly, while God may know the details and span of one's life, that does not mean he is orchestrating it.
Questioning can be tricky; and often there are not clear, easy answers. However, it does seem much better and much more logical than the belief that everything in life is random, or that God chooses suffering for His people. His presence is there-- even in times when it does not seem to be.