Hello,
The various causes of breast soreness are fibrocystic breast disease, ductal ectasia, mastitis(inflammation of breasts),galactoceles, benign and malignant pathologies of breasts, referred pain from liver or musculoskeletal system, arthritis of the
ribs,costsochondritis and inflammation or sprain of pectoralis muscle.
I feel that an examination by a gynecologist will be the best.