God has not promised that we will be exempt from problems and suffering, just because we believe in Him. Christians get cancer and have accidents and suffer heartaches just like everyone else. Jesus said that God "sends rain on the righteous and the unrighteous" (Matthew 5:45).
In fact, we may be called upon to endure even more suffering because we belong to Christ. Jesus warned, "No servant is greater than his master. If they persecuted me, they will persecute you also" (John 15:20). It may be the simple scorn of a former friend -- or for believers in some parts of the world today, it can mean imprisonment and death because of their faith. The Bible urges us to pray for those who are persecuted for their faith in Christ -- and we need to heed its command (see Hebrews 13:3).
Does this mean God has forgotten us when hard times come? No, not at all. God's love never changes; He loves us when times are pleasant -- and He loves us just as much when times are hard. No matter what we're going through, we can turn to Him for strength and encouragement.
We don't always know why God allows hard times to come to us, but we all experience them, and when we do, our response should be one of faith and trust. Remember: Jesus knows what it is to suffer -- for He endured the suffering of the cross. Always keep your eyes on Him.