I just changed o2 bank 1 sensor but the engine light came on again what else could it be

What is your question?

I took my car to AutoZone and had them do a digital reading. It came back as my o2 sensor. Not knowing there are two i replaced the back one then found out i needed to replace the other but the check engine light came back i haven't gone to AutoZone to get a reading yet, i just hoping it's something i can fix my self

What makes this problem better or worse?

Neither

How long has your 2006 Kia Spectra had this problem?

Few weeks