breast tissue on a mammogram

I found a painful lump about a month ago and went in for my first mammogram and ultrasound today, I am 32.  They told me that they found a mass of tissue in the area that was painful and they are not sure what it is.  They did not seem to be worried, but told me to come back in six months to have another mammogram just so that they can compare the tissue.  They ultrasound did not show anything.  I did have a lump removed from my breast about 10 years ago that was benign.   I am not too worried I would just like some more information on the results.
Thank you!!

[japdip]

I would have a talk with the Physician who ordered the mammogram and ask that the entire report be explained to me in detail. Just saying they don't know what it is wouldn't be enough for me. I don't mean that you should worry too much about this but I would demand a better explanation and you are entitled to one.  Regards ...