After I place my Word file into InDesign, the software is adding space after lines that shouldn't have any. In Word, some lines have no space after. But now in InDesign, they do. Is there a way to prevent this? It looks like every line that has a hard return now gains the same amount of space after.
It's likely that your default paragraph style in InDesign includes a space after.
Remove this spacing in the paragraph style definition and your text spacing should be the same as it was in Word.
However, most people who do typesetting for a living prefer to include spacing as part of the paragraph styling rather than adding additional paragraph returns between paragraphs.