Dear adelaide1990: Breast Cancer is extremely uncommon in women in their teens. There are many possible explanations for breast pain, the most common being cyclical pain (pain related to the menstrual cycle). Most breast cancer is not painful. Since you are concerned, you should bring this to the attention of your physician who can do a breast examination and determine if any other testing is necessary.
forgive the personal questions but have you performed a breast exam? do you feel anything different? do you have any discharge? and most importantly, have you seen a doctor?