<s>[INST] I am going to a doctor on Tuesday, but am going out of my mind thinking about this...maybe you can help.  I used to have a small lump in my breast that seemed to go away (this was about a year ago) A week ago it seemed to have returned, only now, it hurts and is a lot bigger.  Nothing is excreted and it is located behind my nipple.  I went into the shower today and noticed that there was a lump of some sort (maybe just like a pimple but a bit bigger) under my arm which popped but still is hard, raised and red.  What are the chances of someone that is about to turn 27 (who has had 4 children) having cancer? is it true that if it were cancer it would not hurt? [/INST] Welcome to Chat Doctor. 1. If you are my patient I would have examined first and ask for an ultrasound examination of the both breasts.2. Ultrasiund will assess the nature of the lump and its sours and where all its extending (like solid, cystic, ductal)3. According to the findings a mammogram would be helpful for things which can not be seen on the ultrasound, like calcifications.4. In your case I suspect ductal dilatation, the scan will help to determine.5. Chances of cancer is less at this age, it progresses differently in different individuals. Good luck. Hope I have answered your query.Anything to ask do not hesitate. Thank you. </s>