Custom module is not showing up for regular user
user_access(), the access handler used by default from Drupal when no other access handler has been set, returns TRUE (the user has access to the menu) only when the permission string is one defined from a module, and the user has that permission.

If "ask question" is not a permission defined from any module with hook_permission() (Drupal 7 or higher), or hook_perm() (Drupal 6 or lower), then you will get an access denied error. 

Once you are sure a module (including the one you are developing) defines the permission you want to use, be sure the same permission is assigned to any of the roles the currently logged-in user has. For example, if the user has the role of editor, then the permission you are using needs to be assigned to the editor role, or to the authenticated user role.