Always use a non-proportional font for printing lyrics. With one of these, each letter and space takes up the exact same width, so characters on different lines always take the same width, hence they don't move relative to each other.

If you use the full reply box, rather than the quick reply, the box at the second to far right is a text font selector. Paste your text into the box, highlight it all, then select 'Courier New' as font type. (This is Courier New)

The chords and lyrics should now line up (if the original came from a non-proportional font source, which many web sources are).

Hope this helps.

EDIT... Seems that your lyrics and chords were not lined up well in the first place, or didn't use a non-proportional font originally. But if you edit them for spacing and use Courier New, they should be copyable without shifting in future.