I just noticed a lump on my 3 week old daughter under her nipple, is this normal ?

Usually: Some of the hormones you made during pregnancy passed into baby.They can produce a degree of breast bud/tissue swelling on one or both sides in both male and female infants. It may be present at birth or come up later, but it fades in most after a few months.Rarely an infection can get into the milk ducts and cause an abscess. If it swells fast and develops redness,have it seen.