What causes breast lumps? What other than cancer could cause lumps or changes in my breast?

Benign and malignant. There are both benign and malignant causes of breast lumps. Lumpy breast tissue associated with benign fibrocystic change is a common finding and is often tender and symmetric fibroadenomas are common benign breast lumps that are seen in young women breast cancer presenting as a mass is a later sign if you have a breast lump please see your doctor for an exam.
Cysts, benign mass. Cysts in the breast can feel like lumps. Benign masses called fibroadenomas can also develop and feel like masses.
Many possibilities. Most breast lumps are benign. Fibroadenoma, breast cyst, infection, fibrocystic change are among the most common benign types.