Hi,
If you haven’t noticed any abnormal features on breast self-examination like a breast lump, nipple discharge or skin changes, I would doubt that the pain you are describing is associated to breast cancer. The pain in your breast could be due to many benign causes like injury to the breast tissue, a pulled muscle, a pinched nerve, Costochondritis which is an inflammation of the cartilage that connects a rib to the breastbone and it could also be caused by an improper posture.
As you can see there are so many factors that cause this pain, but to be on the safe side, it’s important that you make an appointment with your Doctor and check it out so that your condition can be evaluated and find out the cause of your discomfort.
Best wishes..