Where does redemptive suffering fit in with healing?
We believe what the Church teaches: there is absolutely no conflict between seeking healing from Jesus and offering up to the Father in union with Jesus one’s suffering that results from unhealed sickness or infirmity. The Church’s teaching on redemptive suffering, especially as articulated by John Paul II in his Apostolic Letter Salvifici Dolores (1984) is a profound truth that can help us grow in holiness and intercede for the salvation of the world. For example, in the absence of physical healing we can simply offer our suffering up as a prayer to Jesus like St. Paul modeled in Colossians 1:24 "Now I rejoice in my sufferings for your sake, and in my flesh I complete what is lacking in Christ’s afflictions for the sake of his body, that is, the Church." The paradox of our faith as witnessed by the New Testament and the tradition of the Church is that God is so good that he not only can save us from evil but also save us through evil. Look at the cross of Christ: the worst evil ever to happen in the history of the world is transformed by God into the greatest act of saving love in the history of the world.
Yet we must remember, however, Jesus commanded his disciples to heal the sick (cf. Mt 10:6-7, Lk, 9:1, Mk 16:19, etc) and to "visit the sick" (Mt 25:36). The early Church and the Church in history has witnessed Jesus heal the sick even as the Church cares for and loves the sick by developing healthcare for the sick including building hospitals and clinics. How does all of this fit together? Each of us is going to die one day, likely from an illness or a sickness. The point of Jesus’ coming and his commission to the Church to heal the sick wasn’t to establish some silly expectation that everyone is going to be healed in this life. After all, even Lazarus who was raised from the dead by Jesus had to die again. The point of commissioning us to pray for the sick is to preach the gospel in such a way that the goodness of God is on display so that people would accept the truth of the gospel and be saved from sin and death for eternity. Jesus demonstrated the power and love of his kingdom by healing the sick because those healed from sickness in His name revealed to an unbelieving world the power of the kingdom to which he invites us to in eternity. Jesus invites us into this mission.
So in this life we press into Jesus with faith seeking healing. But if we are not healed in this life, we can have great confidence that Jesus can use the suffering we offer to him for his redemptive purposes. That is how good our Eternal King really is!