I'm doing an assignment in which I am summarizing a short, (6 paragraph), section of an article. I have my summary written, with my complete MLA citation. However, I just noticed that the instructions specify "in-text citations" for the summary. Does this imply that I'm supposed to put "(Author pgnum)" after every sentence?
No, you are supposed to place the in-text citation after the quote or paraphrase. In many scientific articles, the author may begin with "In __________'s study, blah blah blah. (in-text citation) Sometimes, the author may use semi-colons instead of a period to illustrate that everything is part of one sentence, and that the semi-colons are merely pauses. Other times, the author may use periods. In that case, the in-text citation will still go after the quote or paraphrase. It is very typical of scientific authors to include many citations in one research paper/publication.