Altitude Pro and similar parallax themes have all layouts set to the front page. To make your Pages and Posts show the sidebar, you must choose that option when you create the Page or Post.
Scroll down underneath your Page or Post. Keep going until you see –
The layout is set to the default. You can change this by clicking another layout.
When you click on the layout of your choice, it doesn’t seem to change – but it does! Click Update and have a look.
In this short video, I change the default layout to a layout with sidebar on the right.