Sometimes the view transformation controls become frozen and just won't let me move around the scene. If I copy and paste my objects into a new scene, the problem goes away. Why does a scene get locked up sometimes?
You are likely experiencing a problem that blender has with the Viewport navigation where it becomes progressively less responsive.
Try pressing Numpad., or use Shiftb to drag out a Zoom To Area box.
This restores the view navigation function.