God does not promise to bless Christians by removing suffering, but to bless us THROUGH suffering. Jesus suffered not so that we might not suffer, but so that in our suffering we would become like Him. God uses our suffering to bring about good. Sometimes this involves circumstances but other times the “good” God works is in our character.
In 2 Corinthians 12:7-10, Paul talks about a great, unnamed, painful “thorn” which God would not remove despite repeated prayer. Paul says that the “thorn” is meant for good because it humbled him (vs. 7) and strengthened him (vs. 9). The pain and weakness brought Paul to a deeper dependence on God’s grace.