A priest is a member of the Roman Catholic Church who has been ordained, while a pastor is someone from any religion who ministers to people in some form.

The distinction between minister and priest might be better understood as the difference between secular and clerical roles.
A minister usually does not have access to certain religious rites such as baptisms or last rites (often with an exception made for emergency situations). They are also prohibited from celebrating mass, which involves consecrating bread and wine in symbolic remembrance of Jesus Christ’s Last Supper before his crucifixion. Generally speaking, priests offer Mass on Sundays while lay leaders take care of services during the remainder of the week. Another responsibility most priests have is hearing confessions.