About breast lumps for 11 year old girl. can the breast lumps be tender when they are growing?

Yes: Breast buds form as the result of exposure of the breast tissue to estrogen. This typically happens at the onset of puberty. The breast buds can be tender. See your doctor if there is overlying redness or discharge.

Thelarche: The breast bud, a spongy clump of breast tissue with an overlying nipple projection, occurs early on in the transition of puberty. It can occur on one side at a time or together. It is often sensitive to touch & hurt if pressed.