I Have Found A Lump In My Right Breast. I

i have found a lump in my right breast. I do have implants. I have recently had R shoulder surgery 4 months ago. I know this lump was not there. I am starting to do my exercersises to strenghten my shoulder, could this be a result from that surgery. I have had a mamo, a ultra sound and a cat scan of the breast, still no one can tell me what it is. They are saying it is a large hard mass, that is 25 centimeters large. I am going in for a ultra sound bi-opsey in a few weeks. do I have anything to worry about?