Matthew 6:25 "Therefore I tell you, Do Not Worry about your life...”
1st Thessalonians 5:16,17 “Be Joyful Always; pray continually;
1st Peter 5:6,7 - “Humble yourselves, therefore, under God's mighty hand, that he may lift you up in due time. Cast All Your Anxiety On Him because he cares for you.”
Philippians 4:4 - “Rejoice In The Lord Always. I will say it again: Rejoice! “
Philippians 4:6 - 9 “Do Not Be Anxious About Anything, but in everything, by prayer and petition, with thanksgiving, present your requests to God. And (if you do this) the peace of God, which transcends all understanding, will guard your hearts and your minds in Christ Jesus. Finally, brothers, whatever is true, whatever is noble, whatever is right, whatever is pure, whatever is lovely, whatever is admirable--if anything is excellent or praiseworthy--think about such things. Whatever you have learned or received or heard from me, or seen in me--put it into practice. And the God of peace will be with you.”
Romans 5:3 - 5 - “. . . we also Rejoice In Our Sufferings, because we know that suffering produces perseverance; perseverance produces character; character produces hope and hope does not disappoint us because God has poured out His love into our hearts by the Holy Spirit.”
The people who wrote these things were speaking from experience. Jesus of course gave His followers the command to not worry as the pagans do. And Paul, who had given His life completely to the service of Jesus knew the benefits of that relationship. I too can tell you from experience, You do not need to live as the pagans live; you "do not need to fear what they fear." If you are in a healed relationship with Jesus, then everything, EVERYTHING that happens in your life WILL be used for your good, God's glory and the furthering of His Kingdom. All you have to do is stop resisting, stop fighting, stop worrying.
Besides - A little pain never hurt anybody.