I'm not pregnant (according to a home pregnancy test) but I'm lactating. My breasts are so sore and swolen a bit. I don't know what this means, could it be dangerous? I'm not taking any medications and I am not nor have I recently have been on any birth control. My periods have been off but I haven't missed any.

Have you been taking Motilium for indigestion? It's an over the counter tablet, and one of the side-effects is to increase milk supply in breastfeeding mothers, and cause lactation in other women.Or even in men.

If not, I would go to the doctor. Lactation can start early during pregnancy and continue for a very long time after birth/weaning. But if you have never been pregnant, then it's a cause for concern.