Definitely get it checked out. It may be just a cyst or it could be something far worse. Not knowing and living with the apprehension is far worse. These days there are so many ways of dealing with Breast Cancers that they are no longer life threatening if they are caught early

I am always careful and get regular mammograms. In my case breast cancer does run in my family. My mother died of breast cancer when I was 13. She had discovered a lump in her breast and it turned out to be cancer. She had let it go too long and it was already stage 4. Too late for her. She was only 48.

I have been fortunate so far, but I do examine both of my breasts for lumps at least every month. With cancers if is much better to be proactive. There is a fairly high probability that it will be benign but you can not afford to not know.