en_tn/rom/09/02.md

that for me there is great sorrow and unceasing pain in my heart

Here "unceasing pain in my heart" is an idiom that Paul uses to share his emotional distress. AT: "I tell you that I grieve very greatly and deeply" (See: rc://en/ta/man/translate/figs-idiom)

great sorrow and unceasing pain

These two expressions mean basically the same thing. Paul uses them together to emphasize how great his emotions are. (See: rc://en/ta/man/translate/figs-doublet)