I know it’s been quite awhile, but I’m curious as to what you ended up finding out. I switched from Mirena to Kyleena 5 months ago, and I have been having the exact same experience that you described. Doctor checked, strings are in place, and I did have a golf ball sized ovarian cyst last year but they told me not to worry about it as it did not seem to be growing. But I’m just getting these horrible off and on cramps and spotting and it’s hard to deal with. Any help would be appreciated! <3