There are several things it could imply. Firstly, she might be attracted to your creativity. A good story often shows that you have an imaginative mind. Secondly, if your story was personal, she may feel a closer connection to you now. She could be seeing you in a new light, as someone with depth and interesting things to share. It could also be that she is just being polite, but if she shows other signs of interest like asking more questions about you or your story, then it's more likely that she has a genuine interest in you.
Yes, it usually means something. Firstly, it shows that she at least took the time to read or listen to your story, which is a positive sign. It could imply that she values your perspective or creativity. If it's a personal story, she might be trying to get to know you better. It could also be that she simply enjoys the type of story you tell and wants to encourage you to share more. However, it's not always a clear - cut sign of romantic interest, but it does suggest some level of positive regard.
The boy might ask the girl what she liked about the story specifically. This can start a conversation and help him understand her better. It also shows that he values her opinion. Maybe she liked the plot, the characters or the way it was told. Then he can create more stories based on what she likes.
It often means she has some sort of interest in you or what you're sharing. It could be that she wants to be part of your social media circle in a more engaged way. If she consistently likes your stories, it might be an indication that she enjoys your presence on Instagram. However, don't overthink it too much, as some people just like a lot of things on Instagram without deeper motives, but it's still a positive sign.