What AV software are you running?
What exactly, where, and how is the notification appearing?
Scanned 13 times over what time span: a day, a week, a month...?
AV programs should be running in the background but as an end user you should be able to set both the type of AV scan and the frequency of scheduled scans.
Update your post to include full system hardware specs and OS information.
There could be other things going on and the system, for example, may not meet the requirements for a "speedy" scan.