My thumb swells up from taking notes in class or barely bumping then hurts to where I can't move it fractured growth plate 4 years ago is that why?

Possible. If that was the same side as the injury, it could absolutely have something to do with your current symptoms. Since it is causing problems, see a hand surgeon for a consultation. There may be some physical or occupational therapy that could help, but you want to make sure there's nothing wrong that requires an operation as well. Hope this helps!