If you owed $1000 or more on the tax return  then the IRS can penalize you if you didn't pay in enough in advance so that is why you got a bill.  To avoid an underpayment penalty you need to withhold enough from places like W2 or 1099 forms OR  you can make estimated payments which is why the program populated those forms  you are not required to use. 

Do I need to make estimated tax payments to the IRS?

PAYING ESTIMATES
For SE self employment tax - if you have a net profit (after expenses) of $400 or more you will pay 15.3% for 2015  SE Tax on 92.35% of your net profit in addition to your regular income tax on it. So if you have other income like W2 income your extra business income might put you into a higher tax bracket.

You must make quarterly estimated tax payments for the current tax year (or next year) if both of the following apply:
- 1. You expect to owe at least $1,000 in tax for the current tax year, after subtracting your withholding and credits. 
 
- 2. You expect your withholding and credits to be less than the smaller of: 
    90% of the tax to be shown on your current year’s tax return, or 
  100% of the tax shown on your prior year’s tax return. (Your prior year tax return must cover all 12 months.)