Remove shading in numbered headings

[Marcia]

Hi. I'm getting headachy unsuccessfully searching for an answer to a shading problem. I have a numbered list in a table. In one of the list, I manually shaded a text just as a mark to return to later on. But when I clicked in the heading styles, the manual shading was applied to all the texts with the same style. I tried Ctrl+Q, Crtl+spacebar, Find and replace highlight, checked the pattern and shading of the heading styles are clear and cut the text and pasted it as non formatted text but the stubborn shading remained.
When I tapped Ctrl+Q, the numbers were likewise shaded, so now I have shaded numbers and texts.
Any idea on how to remove the shading please? Thank you.