When creating an iOS application end to end, should you first create a first or back end?

I have been a developer for 10 years (not iOS), and working on a large company has never created an application to complete. Just worked on very large applications, to pieces.

I am starting to enjoy iOS and I have the application that I want to create. I connected everything using the interface of the iOS application. Since then I started to start coding. I have about 15 scenes in the storyboard (the general application will probably be 100+), and now I just use hard-coded "fake" data.

However, I recently started to think that maybe I need to create a database and some raw data instead of using all of this hard-coded fake data.

Does anyone have suggestions and reasons why one way is better than another?

Should I create a back end in front of the front end? If I do this, then every new scene that I add, I can work with real data from the very beginning instead of replacing fake hard-coded data.

In addition, I know little about creating back ends. The application that I am creating does not look like twitter, but to access the data and for this example, let's say this. The main form of the application is something like twitter. The user can hit the update and get many new data points (“tweets” on Twitter) from the server. Thus, the application can be very intense. Is it better to use something like Parse and pay for their services, or create something in LAMP, or something else. Over the past 10 years, I have worked a lot with SQL and the database, and I really like this aspect of the back end.

Thoughts? Suggestions?

Thank!