“Is there a hierarchy of project managers in project management?”

Not really, although some organizations will have Project Manager 1, Project Manager 2, etc. Some will have Project Manager, Senior Project Manager etc. The more experience you have, the bigger the projects you’re likely to manage (and/or the projects with more risk.)

In some organizations the term Program Manager is used to refer to someone that manages a group of related projects, with a project manager in charge of each project. The term Portfolio Manager can also be used to describe a manager of project managers.  These are often, but not always, seen as being more senior than project managers.  (The term Program Manager is also used by some organizations instead of Project Manager.  This is common in parts of the US government for instance.)

Some organizations might also have a Director or VP of Project Management. Titles such as Project Coordinator, Project Expediter, and Project Lead can be used for individuals running projects without the full responsibilities of a Project Manager.  Finally, many projects are run by operational personnel, who’s title is more reflective of their operational role, than their project management responsibilities.  (e.g. HR Manager, Engineering Manager, Senior Engineer.)