What I infer from this is that breaking a warding on dreams would be like battering through a shield; it causes a certain amount of pain. Because she has not shown (at this point) a desire to cause Rand pain, I don't think the second sentence can refer to what she would do after accessing the dreams.

I think the Moridin connection is more likely; like in TGS, he wound up inside one of Moridin's dreams, one he forces her into and uses to torture her. The questions are, did Moridin exploit the connection deliberately to create a trap for Rand, and is Cyndane knowing bait or unknowing?