WaituiRob,
If I was a betting man I'd say your
problem is twofold.
At times you end a sentence with a "."and start the next sentence with no space between the "." and the next word. The computer will see this as one word with a "." in the middle, not as two words, and this will affect the pagination.
More importantly, I'd guess that when typing and you get to the right edge of your screen, you may be pressing the "return" key to start a new line, as one would on a typewriter with that old fashioned stuff we used to use, called paper. If I'm correct, this puts a hidden symbol in what you type, and tells the computer to start a new line at that point.
If you just type your sentences and have the correct spacing between words, and allow the computer to sort out when it wants to start a new line, then it should display correctly on all screens, as the multitude of computers out there, automatically paginate for the display, or window width at the time. Obviously you'll still need the return key to start a new paragraph.
Here endeth the class of
sucking eggs 101.