Breast discomfort is rarely associated with breast cancer but can be due to many causes. I don't know of any breast concern that has anything to do with the size of your breast ... large or small. My best advice would be to see a Dr. for a clinical breast exam and perhaps some type of imagery (Ultrasound or Mammogram) to determine the cause of this discomfort. I would think that you might have done this a few weeks ago since you seem very concerned about these symptoms and say you have been suffering for some time. Regards ....
Breast pain is a common breast symptom. The reason for breast pain is not clearly understood, and is not usually associated with breast cancer. Breast pain is sometimes associated with hormonal variations and is then called cyclical breast pain. Non cyclical breast pain does not seem to be linked to hormonal variations and is often localized to one area of the breast tissue. Non cyclical breast pain may or may not be the result of an injury to the breast.
Breast pain is evaluated based on the history of the pain you would give to the health care professional, as well as a physical examination. The need for further testing would be determined based on the above findings. Some recommendations for treatment of breast pain involve simple comfort measures such as a supportive or exercise bra, or application of warm or cold packs. Caffeine avoidance, limit salt intake and reduction of dietary fat may also help
I am glad that you are going to make an appointment to see a doctor (preferably a breast specialist),but you should never fear to do BSE...quite the contrary this is the very first thing every woman should do after each menstrual cycle.
Take care now..and please keep us posted.