I have a pea-sized breast lump age 28, potential cancer risk?

Risk is VERY low!: Any breast lump can be benign or cancerous. Important things are: has it grown, changed, gotten harder, deformed, dimpled the skin, made the skin over it red or swollen, or become associated with lumps in your armpit? At age 28, the chance of a lump being cancer is about 1/10,000 -- which is NOT zero. Please see a breast specialist for an exam, and likely an ultrasound. Good luck to you!

Possible: At age 28, defining a breast lesion should be by palpation or sonography and not mammography. Sono showing a regular solid lesion suggests fibroadenoma. If cystic on sono it should subside or can be aspirated. If lesion is firm and possibly irregular excisional bx needed since while Ca is rare it can occur at age 28.