Alma, I'm answering both your questions in this one answer.  Shooting pains in someone who is still growing are not unusual.  Some people call them growing pains, and they are common in any part of your body that is growing like your breasts, legs, and so forth.  You can read more about some normal parts of breast growth in our Guide to Teen Breast development.  You need to tell an adult about the breathing pain.  I'm not a doctor and can't diagnose or evaluate it.  However, it sounds like something a doctor should discuss with you.  People your age sometimes have problems with allergies or asthma.  Pain is not a typical breast cancer symptom, and even for cancers where pain is a symptom it tends not be constant, not "come and go."