What is the difference between a priest called Father and one called Monsignor and why isn’t Father Jim a Monsignor?
 

This is a good question.

Technically ordained males who have received the second step in the sacrament of Holy Orders and serve in the spiritual realm of the Catholic Church are called Fathers.  We find the definition of the word Father in 1 Corinthians 4-15, 16 and Galatians 4:19.  In these New Testament readings we find the word Father is used to mean a teacher of spiritual things.  The jurisdiction the Fathers have is what determines their titles.

For instance when we hear the term Bishop we immediately know he is in charge of the Diocese (or several parishes) and when we hear the term Parish Priest we know he presides as a pastor of a parish.  Some of the titles however, are given as honorary titles such as Monsignor.

The title of “Monsignor” is a title of distinction given by the Pope to certain priests in the Roman Catholic Church as part of a papal honor recognizing the priest’s service to the greater Church.

So since Father Jim is a PSP (plain simple priest as Father Jim refers to himself) of Immaculate Conception/St. Patrick parish he will not obtain the title “Monsignor”.