Gila, there are a number of different types. Some could be a wake-up call, but others are called yisurin shel ahava. Sometimes a person must go through a hardship so that if he still keeps the mitzvos despite the difficulty, he gets a much greater reward, because of the principle of l’fum tzaara agra (in accordance with the pain is the reward).
There are many tzaddikim who suffered terribly, and these were yissurin shel ahava. Since we never know what the source of a person’s suffering is (only the person himself can know if he did anything that needs fixing), we therefore are never allowed to say or think that because he did x he got y. Only a navi can know the truth about another person. Our job is only to have rachmanus and do whatever we can to help the afflicted individual, never to judge.