My spouse has TMJ, and she has had to take powerful medications to keep it under (poor) control. I have seen what you face in the strain on her eyes. I have other members of my family with more dire diagnosis's.
The words and promises of Jesus never said the faithful would live without pain. Even He cried out in pain and doubt on the cross. We all suffer in this vale of tears, and we should remember that our prayers to God have never been based on a transactional relationship. God does not remove pain, because we ask for Them or offer something in exchange for this relief.
When my son was 20, he had a psychotic break while attending college. Since that first break, he has had recurring incidents where he believes he is dealing with CIA agents, zombies, cannibals, and other delusions of mental anguish that come right out of a Bosch painting. Doctors diagnosed him with schizoaffective disorder, and he has been taking drugs for six years with side effects that are barely less than the symptoms schizoaffective disorder brings to a person.
While he was going through these recurring episodes and battling with his own disbelief in what was happening to him, I fell into a long bout with despair. I sought therapy for myself, and eventually ran across "Man's Search for Meaning" by Viktor Frankl. Reading it helped.
Today, my adult son lives with us at home, and he probably will until my wife and I die. The disorder is under control of a sort.
When the world brings us pain, it is a lesson. When the World piles pain on top of pain, and it seems there is nothing but indignity and pointless suffering, find the grace at the edges of your perception, in the actions and spirits of these around you. The suffering is a challenge to the meaning and order to the cosmos. When you are facing the pain in your own life, especially when it seems to be without end, it is your duty to find meaning in that suffering rather than rail against a sense that God is denying you simple relief.
You can endure this pain. You really have no choice. I am reminded of the words of Julian of Norwich,. She said, "All shall be well, and all shall be well, and all manner of thing shall be well."