If you are receiving a Form 1099-NEC, you are being treated as an independent contractor by the company paying you and you need to file Schedule C for your self-employment income.
The company that hired you did not consider you their employee. If they did, then you would have been issued a W-2 and not a 1099-NEC. Therefore, you are responsible for paying the Social Security and Medicare tax in the form of self-employment tax.
The good news is that you can also claim expenses related to your work on Schedule C. This will help to reduce your income tax and your self-employment tax.
Take a look at the following TurboTax articles for more information: