I am 24 with 2 children and had mirena inserted in February after going crazy with implanon. I have never really tolerated the pill either and this was the last option. 2 weeks later I was in excruciating pain in my stomach that i could barely look after my kids. My stomach was so distended i looked about 8 months pregnant. After tolerating the pain for a few days i went to my doctor and she sent me for a pelvic ultrasound. they found cysts on each ovary. 1 measured 3 inches in diameter and the other 1 was slightly smaller. Even after they dissolved i was in pain for at least a month afterwards due to my bowels and bladder being pushed around. Since then I have had no problems (touch wood) I have had minor cysts in the past but not to this extent and after doing some research found that mirena caused it. I have opted to leave it in for the time being as i am not having any other side effects that i know of from it. But if I end up getting cysts again I will definitely be getting it taken out.