I use many different versions of the bible. Each translation tend to clarify a point or help me see the point in a different light. If I am still not sure, I read the JFB which attempts to talk about the translation in the original Greek or Hebrew context. If I still want to investigate, I go to http://crosswalk.com and check the Greek or Hebrew lexicons for the actual meaning.
Okay, surprisingly or maybe God-incidently, I read a verse of the day site often and the prayer of Jabez came up. So, I decided to do some research.
I think that the NKJV translation took the definition literally from a Hebrew definition of the original transliterated word called "atsab". There could be several definitions of "atsab". One definition is "Hiphil" which means to cause pain. The other versions probably used the Hebrew definition
"Hithpael" which means to feel grieved, be vexed. I believe that the context of this scripture is for God to remove grief from Jabez as his name was literally called "grief" by his mom because she bore him in grief or pain.
I believe that the other translations then seem to be more appropriate. The NASB version also uses the word pain but in the proper context: and that You would keep me from harm that it may not pain me!.
You know what I love about this scripture? It tells me that if we are ever in a position that caused us grief or sorrow, and we called on God to help us, He will. I believe God loves helping people who have been in unjust positions due to no fault of their own.