I am using a themes on shopify but I can only edit the home page from within the actual theme whereas other pages can only be edited from with shopify.
Its terrible trying to create a page in shopify........I have to switch between shopify and the theme to see how the page looks.
Is this how it works or have I missed something?
Building Pages using a theme is not a straightforward task which is why Page builders apps are useful in that sense. You can create any layout without having to delve into the code.
One app we recommend to our clients is GemPages, you can install it for 10 days I guess and try it out for free.
Let me know if that solves your issue!