Dear Tilli,
Have you ever been told that you have fibrocystic breasts? You may be experiencing a benign cyst that can fill up with fluid, and cause pain. I have had several friends and relatives with this condition, which is rather common. Especially in younger women. I would follow the advice of the nurse here, but I would not worry too much until you get another opinion. If you have other family members such as your mother or any sisters or cousins, ask if any of them have experienced this problem. Usually pain is a better sign in breasts, as far as I have heard, than no pain. Some women I know have had to have those things drained at times, due to the burning and pain they can cause. Best wishes, and take care of yourself. Try not to worry. It has never done me any good. I just had a biopsy done yesterday, and I was so worried about it, and now that I had it done, I wish I had known it would not be bad at all. God bless!
Dear tilli, without ability to view the films it is difficult to say what it was that you saw on the mammogram. An option for you may be to seek the opinion of a breast specialist (these can usually be found in large academic centers). They can evaluate your symptoms in context of the test results (reviewing the films), physical examination and discussion.