About a week ago I noticed my 5 year old daughter has a lump behind her left nipple. The lump is maybe the size of a pea. Her nipple looks swollen due to the lump. She says it only hurts when someone touches it. The lump seems movable. There is no discharge coming from her nipple. She has no symptoms of puberty or anything else with it. When she was a baby she has very small lumps under her nipples after she was born which we were told was due to pregnancy hormones and breastfeeding. But, those had eventually gone away. Do you know what could be causing this in a girl so young? Is this something that will likely go away in time? If so, how long might it take?