Dear dnicole: Typically, one hears about mastitis associated with breast feeding. However, since this is a breast cancer forum, the question about the incidence of mastitis in young women without children might be better posed to your doctor. Mammography is not generally recommended in young women (<35) because breast tissue tends to be dense, making interpretation of mammography very difficult. If there is a lump, an ultrasound may be valuable to determine if it is cystic. If a lump remains and can be felt, it might be valid to biopsy. It is a good sign that the problem resolved with antibiotics. You might consider an opinion with a medical breast specialist who can examine you and make recommendations as to appropriate interventions and follow-up.