Yes, God may use tragedies or heartaches to bring us closer to Himself. I've experienced this in my own life, and I've observed it in the lives of others also.
Does this mean God is being cruel when He does this? No, not at all; in fact, the opposite is the case. The problem, you see, is with us, not with God. Our hearts easily become cold and indifferent to God, and we refuse to listen to Him when He's trying to get our attention. We can even become so hardened toward God that we can't hear His voice. When this happens, the only way He can get our attention may be to allow something to happen to us that will shatter our indifference or rebellion. Only then will we face our need for Christ, and turn in faith and trust to Him.
Just as we discipline our children so they'll do what is right, so God sometimes disciplines us so we'll turn to Him and follow Him. The Bible says, "No discipline seems pleasant at the time, but painful. Later on, however, it produces a harvest of righteousness and peace for those who have been trained by it" (Hebrews 12:11).
Not every difficulty in life comes to us for this reason. But when hard times come (as they will), we need to ask what God may be trying to teach us through them. Most of all, we need to turn to Him for the strength and patience we need. Never forget: God's love is strongest when our own strength is weakest.