Create a new paragraph style from the Paragraph Styles panel for your body text. Select the paragraph of body text and apply the paragraph style. For header create another paragraph style and apply that paragraph style. After editing the header don't enter a hard return. Separate the header text frame from the body paragraph text frame.
Thanks PrintFusion45, I do use paragraph and character styles depending on the job but it is just another work around that takes time.
It doesn't matter if I do a soft or hard return.
I will usually use separate text frames for headings but if I have sub headings or other bold/italic/different text within my copy it is still a problem.
I'm not sure there is a fix to my problem - it is just really annoying, inefficient and doesn't make sense for it to happen this way - sigh.
The basic InDesign workflow says that you have to do a local override, if you need multiple styles within the same paragraph. In this case you have to use a hard return after typing the heading or subheading to separate the body text from their respective headings. Creating paragraph styles may be time consuming but is a good practice and can be reused trhoughtout your documents if you're working with a book.