I changed passwords and am getting constant notifications that my account needs attention, why is this?

Answer 1

Scam? This is how to identify legitimate Yahoo websites, requests, and communications: https://help.yahoo.com/kb/SLN2091.html

Answer 2

Probably someone else is logging with your account, maybe your wife/husband. I recommend you if it happen again to change account and trasfer all the files on the other as you have no more problems