why are you asking me to file business tax if i filed my personal tax and added a side job i started last year

If you "side job" is self-employment, that is treated as a business, and subject to business taxes.

If instead, your "side job" is working for a employer as an employee, you would probably have received a W-2 form from that employer.

If you are self-employed, you may wish to refer to IRS Publication 334, Tax Guide for Small Business at

https://www.irs.gov/pub/irs-pdf/p334.pdf

I hope this helps.

The IRS considers the income from your side job a business. You are considered self-employed and will complete a Schedule C which is how you report your self-employment income. The good news is that you can deduct ordinary expenses that you incurred making this income.  Follow the steps below to enter your income.

1. Launch TurboTax
2. Select  Wages and income
3. Select Self-Employment Schedule C:1099-NEC
4. Answer Yes on the next screen - Did you have any self-employment income or expenses?
5. Answer the questions on each screen, when you get to the screen - Let's enter the income for your work, select the form from your income or cash 
6. Scroll through the screens to enter your information
7. Continue going through the screens to enter your expenses.

For additional information, review the TurboTax help articles: How does my side job affect my taxes?, How do I report income from self-employment? and  Where do I enter my self-employment business expenses, like home office, vehicle mileage, and supplies?