This invention relates to: (a) compounds and salts thereof that, inter alia, treat pain; (b) intermediates useful for the preparation of such compounds and salts; (c) compositions comprising such compounds and salts; (d) methods for preparing such intermediates, compounds, salts, and compositions; (e) methods of use of such compounds, salts, and compositions; and (f) kits comprising such compounds, salts, and compositions.