Yes, it is possible to rejoice in suffering. Why?
Several reasons come to mind when I think of suffering as a cause for joy.
Here are a few:
One, God is asking one to be purified so that He can come and dwell within a person as the Holy Trinity. Therefore, suffering is a sign of the elect.
Two, suffering purifies one from sin and concupiscence.
Three, suffering causes one to prioritize one's life and focus on what is important-Jesus and one's relationship with Him.
Four, suffering is an invitation to share in the Passion of Christ-what a gift.
Five, suffering frees up the virtues and gifts of the Holy Spirit so that these can flow and build up the Church.
Six, suffering can be added to intercessory prayer. Add the suffering of arthritis, for example, to those prayers for someone in the family who has fallen away.
I offer my horrible foot pain today, for example, for a certain seminarian here at Mundelein.
Seven, suffering can be offered for the release of a holy soul in purgatory.
Eight, suffering causes humility. One is not in control, God is.
Nine, suffering joins one with others who are suffering as well in compassion and empathy. One can join a little bit with Mary at the foot of the Cross, and others who are suffering today.
Ten, suffering is salutary for others in the Church is one is joyful, teaching others to, likewise, be grateful and rejoice.