If I am referring to her “sick breast” as one of the excuses she uses, do I have to cite where I got "sick breast" from?
Yes. Anything that is a direct quote, such as this appears to be, would need to be cited. The citation, internally, would be (Malamud 238) or whatever the page number is. If you are only dealing with one of his novels, as I assume you are, then there is no need to continually cite the novel itself.
After your first citation, and until you reference another critic or author, you need only need cite the page #. So, let's say the first sentence is: For the protonist, "baseball was the best game that ever was" (Malamud 238). He believed "wholeheartedly in the game" (250).
Also, if you have already mentioned the title and author of the novel or article you are quoting, then repeating the author's name in the citation is unnecessary.
You can find some good samples of MLA citations at the links I have included below. The first link has a sample paper, the second is a general help page from Cornell University.
Good luck with your paper.