What might a cancerous lump in breast feel like?

Varies: Some times hard, sometimes rubbery, sometimes can't feel at all. Best way to know what it is: get examined by your md. May need mammogram and/or ultrasound to figure it out.

Many variations: Please see your doctor. Given your age, breast cancer is extremely unlikely. However, you need to find out what this is. After a complete history and physical, if there is a palpable abnormality, an ultrasound will probably be next, perhaps followed by a mammogram.