Darlene, are all these chapters in a single InDesign document? So you can see chapter 3, right?
So, Dwayne is saying that the text frames may not be THREADED together. (Dwayne, I much prefer the word “threaded” instead of “linked,” because links are what show up in the Links panel. Or some people would consider documents “linked” in a Book panel.)
InDesign is not like Word, where everything is one long story. In your case, perhaps the “story” (the chain of threaded frames) ends at the end of chapter 2. You can tell by selecting the last frame with the Selection (arrow) tool. If the square “out port” in the lower-right corner has a little triangle in it, it means it’s threaded to another frame. If it has a red # in it, then it means it’s overset (too much text to fit into the frame. If it is blank then it’s the last frame in the story.
From what you’re describing, you should be able to select the text in chapter 3 just by clicking it with the Text tool. If not, it’s also possible it’s locked for some reason.