Growth in 3 months

Yup, cysts and fibroadenomas both could grow in 3 months. Both are benign and harmless. And lumpy breasts certainly can change over time - you are young and were breastfeeding about a year ago, so your breasts might still be changing as a result of that.

Breast cancer? It's possible but extremely unlikely that something would develop into a significant lump that quickly.

I looked back over your history of posts so that I could put see how your current concern relates to your previous problems. You've had 4 different concerns over the past 14 months, first you were convinced you had IBC, then you had a breast lump with associated neck and back pain which you thought was metastatic breast cancer, then a letdown feeling which you believed was a sign of breast cancer, and now this further lumpiness. You've never come back to close out on any of your previous concerns so I'm assuming that they all turned out to be nothing serious.

Normal breasts can be lumpy. Breasts have skin that develops skin conditions. Breasts that have been breast feeding experience lots of changes. It is important to be aware of your breasts and go to a doctor when there is a new and persistent change. But it's also important to not react to every minor change or pimple.

Verdana, chances are that it's benign, but please follow up and do the recommended tests. Also, if they give you the all clear, continue to monitor your breasts for any changes.

My cancer grew very rapidly. I don't say that to scare you, but just so you know to be aware of any changes, and let your Dr know if something seems different. Best wishes to you.