No matter which destination or area of cover you select when you buy your policy, your LV= travel insurance will not cover you if you travel to somewhere the Foreign, Commonwealth and Development Office (FCDO) advise not to go to. Information from the FCDO can be found www.gov.uk/foreign-travel-advice or by calling 020 7008 1500.
If you've selected Worldwide cover (including the USA) there are no other restrictions on where you can travel (other than if travelling against FCDO advice).
Please check your policy documents for the area of cover you have selected.