You and your company both are two separate entities. Your company is in US, therefore it has to pay taxes in US. Therefore, when you receive the stocks, you don't have to pay any taxes in US as your company is already paying taxes in US.
As you are staying in Argentina, you are using the public resources like road, governance, security (police), justice, etc; it makes you liable to pay taxes there. You have to pay taxes on your income as per the tax rate and slabs that you fall in.

Thanks for reading
Shishir