I just had breast reduction surgery July 30, 2018, 4 days ago, ended up with a lot of side boob, will this reposition?

At four days post-op, it is too soon to determine what the final outcome of your surgery will be. You are still in the very early postoperative period, and you will notice changes as you heal. Without even seeing photos, it is reasonable to say that you have swelling that will decrease with time. At this point, follow the postoperative instructions that your surgeon provided for activity and wound care. Continue to follow up with your surgeon for regular appointments to ensure you are progressing toward your aesthetic goals. I am hopeful that you will have a wonderful outcome that you will be quite happy with!