Observation: It seems that the Prayer of Jabez is so popular because it fits so neatly into what we would like life to be like--expansion of our territory, freedom from pain and trouble. There is no question that God answered Jabez's prayer but it is not at all clear that all of this is God's purpose for most of us--maybe Jabez was the exception rather than the rule. Certainly God wants to expand our territory--He wants to increase the arena in which we can extend Godly influence with our lives and He certainly wants to bless us and be with us.
The part that we may not see happen the way it did for Jabez is being kept from all trouble and pain. It seems that it is God's purpose for most of His kids to train them and grow them as they deal with trouble and pain. We don't want it, of course, but we may need it and, if we respond correctly, it will bring us needed maturity.
In fact, it is in pain and trouble that God's presence is most acutely felt and it is in learning from pain and trouble, and sharing what we learn, that we gain influence and "expand our territory.
It is, in fact, the search for the trouble free life that keeps us on the sidelines, keeps us from pressing forward into God's purposes for us. His purpose for us is not a trouble free/pain free life, but one spent whole dependant on Him to navigate through those times.