I work as a server for a food truck. i got a 1099-nec. why do i have to say im self employed?

[saydeeshark]

why did i get a 1099-nec

[fanfare]

you got a 1099-NEC because you are not a W-2 employee.

It's one or the other.

[MaryK4]

You received a 1099-NEC because the business owner has you classified as an independent contractor.  This means you must pay your own self-employment taxes (usually you pay half and the employer pays half)- so your pay is less because you are going to have to pay the SE tax now if you did not pay estimated taxes during the year.  You also can deduct any expenses. 

See Am I considered self-employed?  and Am I an employee or an independent contractor?

If you think you were an employee, first talk to the food truck owner.  If they do not want to change you to employee, you can contact the IRS or your state and ask them for a determination.