Is it always necessary to include a research question in the introduction of a paper? A question purely out of interest (and a bit of importance, since I'm enrolling in a research master program next month): 

I wondered whether it is always necessary to include a research question in the introduction of a paper. For example, an introduction can also contain a description related to the purpose of writing the paper, right? 

To give my question more context: suppose that you had to carry out a literature study on a specific subject in the field of software engineering for school, where you have to investigate a few methods (how they work and how they are related to one another). In this case, an introduction that explains why the paper will be written and an outline of what methods will be described would be sufficient, right? Or am I wrong? I mean, I don't really see the need to set up a research question, since the paper is more descriptive by its nature in this situation.
If you are writing a research paper it is quite difficult not to have a question in some form. The purpose of the introduction is to set your study (question/gap of knowledge or what have you) in perspective, to narrow the focus down from a slightly bigger picture to the gap you are trying to fill or narrow even further with your study. Even if your paper is a review, you are doing a review for some specific purpose.

So, you may be thinking too narrowly if you think of a question as a sentence with a question mark, the focus of your paper will be your research question, usually a gap in knowledge where you through your study takes our knowledge beyond the current limits.