Thank you for your question!
One thing you might want to see is if your editor is set to display in 2 columns. When editing a post open the Screen Options and make sure that the 2 columns option is selected. This will put all of your post settings in a single column to the right of the editor. If you have 1 column selected then the Featured Image option should appear at the bottom of your editor instead of on the right side.
I hope that this helps you get your editing page working as expected and please let us know if there is anything else that we can do to assist you.