Yes, usually you can share your post to your story. Most social media platforms have this functionality. However, it may depend on the privacy settings of your post and the specific rules of the platform.
There might be some issue with your account. It could be temporarily suspended or have some sort of violation. Or perhaps the story you're trying to share doesn't meet the platform's content guidelines.
It could be that you don't have the correct permissions set. Check your account settings to see if sharing is enabled. Also, make sure you're following the platform's guidelines for sharing.
Yes, you can. Instagram allows you to share other people's IG stories to your own story. Just look for the share icon (usually an arrow) on the IG story you want to share, and then select the option to add it to your story.