It could mean a lot of things. Maybe they still care about you on some level. They might be curious about how you're doing or what's going on in your life. It could also be just a habit. They were used to seeing your stories when you were together and they just continue to do so without any deeper intention.
In most cases, no. It's normal for an ex to be a bit curious. But if you think they might be trying to cause trouble or manipulate you in some way, then you should be cautious. However, if there are no signs of that, it's probably just a casual thing. For example, they might be scrolling through their feed and your story pops up, and they watch it without any real intention behind it.
It could mean a lot of things. Maybe they're just curious about what you're up to. Or perhaps they still have some feelings for you and are using this as a way to stay connected in a small way.
It could mean that they still have some level of interest in your life. Maybe they're just curious about what you're up to now. It doesn't necessarily mean they want to get back together though.