Hello,
The pain could be due to multiple reasons but a detailed history and examination will be needed. You can now do a self breast examination. It is available online. It will help you locate your pain better. Kindly see a general surgeon for this issue. To reduce the pain you can do a cold pack. Pain killers before examination may lead to a vague diagnosis.
Next Steps
consult a general surgeon, mammogram
Health Tips
Red flags: any redness, swelling, changes or Puckering of the skin over breast or nipple.