Hi my brother is 12 and goin through puberty and has a lump under his nipple that is hard is this related to puberty or not. Quick response apprecited?

Common, goes away. Pubertal gynecomastia will occur in 1/3 to 1/2 of males ; generally last about a year before fading. Intensity varies from small lump to generous boobs. Overweight kids can appear to have it from just fat accumulation. If present after 3 years, surgical removal of the glandular tissue ; liposuction of any associated fatty tissue will do the job.