Preachers preach and teach (pretty much 1st and 2nd Timothy which are letters Paul wrote to the young preacher) pastors shepherd and lead the church, pastor and elder is the same (Titus 1:5) Every christian is a priest (1 Pet 2:9)
I have found a Preacher can be a Pastor or a Priest. However a pastor is generally involved in protestant Christianity, and a priest in Catholic sect of Christianity. Priests also occur in many pagan religions as well.
when it comes in religion, God is prohibiting Christians be called FATHER. if you acknowledge God as your Father, do not call your leader FAther. it is prohibited by God. you can treat your leader or acknowledge your leader as your father in faith but do not call him FAther because christians should only have ONe Father and that is the God the Father.
Jesus said, all ye are brethren.
you should call your leader or preacher or pastor as brother or sister. this is what the Lord recommended. because He said " all ye are brethren."
Matthew 23:9 9 And call no man your father upon the earth: for one is your Father, which is in heaven.
Matthew 23:8 But be not ye called Rabbi: for one is your Master, even Christ; and all ye are brethren.