Why does my tax return amount of $1981 go to owing $1839 when enter SS of $20,304. That is a tax of $3820 on my SS. All other info is enetered.

This is possible if you have substantial income outside of your SS. How much is your additional income?

MFJ, approx $103, 000 before SS entered, and I had a refund showing of $1981, entered SS of 20,304 and now owe $1839

See @Zbucklyo answer below. You can be taxed on up to 85% of your SS income if you make substantial other income. Since you did not have taxes withheld, this is the amount of tax on your SS income that makes the difference from refund to liability.

Also remember that any increase in income can also lower or eliminate some deductions and credits.

Very possible, depending on your other income as up to 85% of social security income is taxable.  If your marginal tax rate is 22% this would be correct.

Answered in comments:

See @Zbucklyo answer below. You can be taxed on up to 85% of your SS income if you make substantial other income. Since you did not have taxes withheld, this is the amount of tax on your SS income that makes the difference from refund to liability.