I tried to log into my AA account and it says that for my security, my account had been locked.

I changed my password and unlocked it with no problem. I didn't have any previous failed login attempts, so I don't think that anything that I did caused the lock.

All my miles and trips seem to be there. There were no unexpected charges (pending or otherwise) on my linked CC. My trip credit was intact. So I don't think anyone accessed my account.

Does this just randomly happen sometimes? Should I be concerned?