Someone locked my bank account?

I have a savings and checking account with Citadel. the Savings account had roughly $3100 in it and the checking had maybe a few dollars. so about 2 weeks ago I transferred money from my savings to my checking just fine. well today I go to see how much money I had in my savings but when I go to log in on the banks website, it says that my account has been locked and to call them for istance. I figured maybe my mom locked it for some reason (Im 17 so she can do that) I old my mom about it and she said she didnt lock it. well the only other person that could have locked it is the bank, but can they do that? if they can then why would they?