Healthcare for foreign pensioners
If you are a pensioner and receive your pension from another EU country but live in Lithuania you should present to the Lithuanian National Health Insurance Fund the form S1. S1 is a certificate of entitlement to health care if you don't live in the country where you are insured. In Lithuania, you should submit it to the National Health Insurance Fund (Valstybinė ligonių kasa). Their contacts can be found here.
If you are a pensioner and receive your pension and are insured in a non-EU country, you are not entitled to a free health care. That means that you will have to pay for the medical services in Lithuania.
Source: National Health Insurance Fund