Within my app there are several views accessible from a side navigation pull-out panel. Is it necessary to put the title in the navigation bar all the time?
First of all, you should always have a navbar in each of your views, so you need to ask yourself what you are trying to achieve by not having the text there.
The iOS philosophy is that the navbar should indicate where you are in the app. Most of the time this is accomplished by a title, but there are some cases where it can be accomplished without on. However this is usually only done on the home screen where other design elements make it clear that this is the home screen.
Facebook followed this philosophy, but they still used text in the navbar when not on the home screen.
That said, I would say that you should have a compelling reason not to have the title in the navbar. For 99% of the cases I would say it is better to have the title, as it is what iOS users have come to expect, and so improves their UX.
From the Human Interface Guidelines (iOS UI Element Usage Guidelines):
So, while not "required" or anything, from a user experience perspective, the title is there to help identify which view we are in. So, the question you want to answer, if you decide to do the logo thing, is: How will my user know (s)he is in view 2 and not view 3?