navigaitonbar back button is not working properly

my problem is navigation bar button is not working properly,that is going forward properly but not going backwards.please solve my problem i tried a lot.but i didn't got. - (IBAction)showLeftSideBar:(id)sender { if ([[SidebarViewController share] respondsToSelector:@selector(showSideBarControllerWithDirection:)]) { [[SidebarViewController share] showSideBarControllerWithDirection:SideBarShowDirectionLeft]; } else [[SidebarViewController share] showSideBarControllerWithDirection:SideBarShowDirectionRight];

}