If the question has been migrated to Stack Overflow, it means the question was about programming. Meta Stack Overflow is the site where users ask why questions have been migrated, closed, or deleted; report bugs found on Stack Exchange sites; propose features for Stack Exchange sites they think useful for other users; ask questions about how things work on a Stack Exchange site.
Migrations from Meta Stack Overflow to Stack Overflow are rare; they are generally done if the question is about Stack Exchange programming, and it is thought to be generic enough to be answerable on Stack Overflow. Otherwise, if you ask on Meta Stack Overflow a question that is for Stack Overflow, the question is simply closed, and deleted. Migrating a question to Stack Overflow is not the way to by-pass a question ban on Stack Overflow. First off, there isn't a migration path from a meta site to the main site; even if there would be such migration path, migrations are blocked, when a user has a question ban on the destination site.
When a question is migrated, also the reputation that has been gained with the post that is migrated is migrated. There is just an exception for questions with a negative score, for which the question score is reset when the question is migrated; this means the OP will not lose reputation when the question is migrated.