I amended my federal tax return from previous year and now I owe State taxes even though my husband worked in another State

Go through the state return carefully to be sure that your husband's income is not being attributed to that state when you made the change from filing separately to filing jointly.  

Based on the situation you described, the amended return has increased the state income amount and you may need to make a further adjustment in the state return to remove his income from that state.

It depends on the state ... switching from MFS to MFJ the base % that the state uses to tax the state income may have changed which will affect the bottom line.

Carefully check the return before and after the amendment to see how this ratio was calculated. 

Thank you. Additionally TurboTax worked it out that we were getting a refund so the TurboTax calculation was wrong on TurboTax