Tragedies or suffering in Islam are not only due to sins.
Tragedies may come to a non believer so that he knows that he is not the one who handle his life and that God is the most powerful, i.e take him back to his roots believing in God.
I know millions of stories where people after having had a tragedy and were close to death started thinking about life and its purpose and became believers, or came back to the right path if they were already believers.
On another hand, there are tragedies that came from sins and that God give to believers in order to be punished by hell in the afterlife, as it minimize their sins and grant them forgivness.
From the last angle, tragedies are given to very religious people to test their faith and how much steadfast they will be, if they succed it will grant them higher degrees and make them close to God, if they fail it will be basically because of insincerity in past deeds or arrogance or appreciating one's acts and being like: " Look God how much I worship you" while by all the worship he does he is not even thankful at the very least for the blessing of seeing while other people are blind.
So finally, tragedies or sufferings are given to different people for different reasons; and each one must be enough smart to see from where it is coming.
And Allah knows best
Allah says in QUran ( 2:155-157)
[SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1]155. And certainly, We shall test you with something of fear, hunger, loss of wealth, lives and fruits, but give glad tidings to As-Sâbirin (the patient ones, ).[/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1][SIZE=+1]156. Who, when afflicted with calamity, say: "Truly! To Allâh we belong and truly, to Him we shall return."[/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE]
[SIZE=+1]157. They are those on whom are the Salawat (i.e. blessings, etc.) (i.e. who are blessed and will be forgiven) from their Lord, and (they are those who) receive His Mercy, and it is they who are the guided-ones.[/SIZE]