SE Tax and Social Security?

[KaneKungFu123]

The money I will pay if i file as a pro called SE tax... it is my understanding that this is a social security tax and that i will get all of this money back at a later date?... is this correct or do i only get a portion of it back? and what about inflation? i am only 19 and wont retire and get this money for 40 years, and 40 years ago a candy bar costed a nickle, so is this whole thing a scam like everything else the government controls?