Hi I appear to have insurance through Obama care that I didn't know I had or ever use. But the IRS says I owe 8031 dollars because of it ?

If you had health care insurance through one of the state Marketplace Exchanges or from healthcare.gov then you should have received a Form 1095-A from them.

Go to this healthcare.gov website to see if there is a Form 1095-A for you - https://www.healthcare.gov/tax-form-1095/

The Form 1095-A was required to be reported on your federal tax return.