The "my apps" that you're referring to are not the apps that are installed in your phone. Rather, those are all the apps that you have installed on and/or purchased for any of your Windows devices. My "My Apps" says that I've got 999 apps, but I'm sure that I don't have all of them currently installed in my phone.
To check for the apps that are in your phone, tap on the three dots at the lower right of the screen, tap on "downloads" then swipe over to "history" - this will show you the list of all apps that are currently installed in your phone* in chronological order. You may tap on each of those apps to see if an update is available. If an update is available, you should see "Update" instead of "View" at the lower left of the screen.
And welcome to Windows Central.
* - This should be the same list that can be found in Storage Sense, but the one in storage sense is ordered differently.