sore nipples & iud

i have the kyleena iud (ive had it for about 5 months now) and my period just now went away. with my first absent period (my pregnancy test was negative just to confirm), i got really sore nipples. they only hurt when theyre pinched or soft pressure is applied but this has never happened to me before its pretty bad. has this happened to anyone else?? i know iuds can lead to breast tenderness but this just seems weird.. could it be an ovarian cyst?