It’s happening because you created an inline image. Basically, you’ve got a column of a fixed width and you’ve placed an image within the column. You’ve then adjusted the image width within the column. When you align the image to the right, because the text is left-aligned the text flows around the image.
Apart from the fact that the thing looks awful and rather dated, if you simply must have this sort of arrangement, you need to add a 2 column bric between the header and the paragraph text (nesting columns within a column). This will create two even columns between the header and the paragraph text. Simply add your image to the second column and then adjust the width of the first column to create the offset you want on the left of the image. Remember, images will always fill the width of the column they are placed in, so just make sure your image is within a column. If you want to adjust the width of the image, it’s better to adjust the width of the column that the image sits in. The paragraph text will then remain below the image. Here is an example: