Hi,
Asymmetry means that there is an area that does not appear normal as compared to the rest of the breast tissue and further evaluation is needed. Until this abnormality is fully investigated, no one can say what it could be.
This abnormality, whether it's palpable or not, could mean a lot of things and doesn't necessarily point to cancer. It is very hard to tell at this point if what was detected is a natural occurrence or something to be concerned about..
Try to stay calm and go ahead with the additional views of the breast to have a more definitive diagnosis. After the Mammogram/Ultrasound views, ask your doctor/radiologist about the BIRADS classification of your mammogram which is a standardized reporting system to know if there is anything to worry about.
This system allows radiologist to categorize the findings by numbers. The scores go from 0 to 6.The higher the number the more suspicious is the abnormality.
I hope this help and wishing you benign findings!