Also, please remove your deodorant with pre-moistened wipes. You'll find materials to read while you are waiting to be called. If you wish, you may watch a video on breast self-exams, or a video how a mammogram is preformed. We compress because we care. As the technician will explain, the procedure is going to be tight, but not uncomfortable.
Compression is necessary to spread the breast tissue onto the plate.
But it should not be painful for you. The technician will always listen if you feel too much discomfort. Additional views may be necessary to see all the tissue. Most of the time, if a second set of films is taken it is not because a tumor has been seen. We simply need to compress a certain spot a bit better.