Anyone experience any breast pain with Mirena?

I have had my Mirena for almost 5 years. I haven't had any problems so far. I am schelduled to have this one taken out and a new one put in next month. However for the last 5 months or so I have had a pain in my right breast. I went to the doctor to have it checked out. She did feel "lumpy tissue" in that breast and I went and got a mamogram (I am 34 so I hadn't had one before) and an ultrasound. The doctors concluded that there wasn't anything there and just to keep an eye on it. Well after 2 months or so, it is still hurting. It only hurts sometimes (I would say about half the time or maybe a little more). I have gotten rid of all my underwire bras and still hurts. I was starting to wonder if maybe this is some side effect of the Mirena or something related to it.

Anyone had this happen??