The four modes of continuous oppression are defined on the previous page 667 in footnote #3.
About the pain of sensual pleasures, since we're still un-enlightened beings, we're still subjected to the "four perversions" as described in AN 4.49 ( http://www.accesstoinsight.org/tipitaka ... .than.html
). Also refer to the leper analogy in MN 75 ( http://suttacentral.net/mn75/en
) who, due to the disease, continues to scratch his open wounds with his nails, or causterise his body over a burning charcoal pit to "feel" better. For the leper, the only way to get to the truth is to take the "doctor"'s medicines to be completely cured, not to dwell on some illusional make-believe about his state.