To answer your question, yes it is possible, but in my opinion it's not advisable. Breast augmentation is an elective cosmetic procedure and every effort should be made to optimize your physical health prior to surgery. For starters, you will be electively subjecting yourself to general anesthesia twice in one week, which is not ideal. You also need to consider the positioning that's required for your breast augmentation. Depending on your surgeon's technique and where the implant will be inserted, you may need to have your arm extended out and strapped to an arm board for the duration of the procedure. This might exacerbate your shoulder pain or put stress on your shoulder incision. This positioning might be contraindicated by your orthopedic surgeon. You might also have a shoulder wound that is not completely healed very close to or even within the surgical field. These factors could possibly increase the risk of contamination. Lastly, you'll have two areas that need to heal. You'll probably have more postoperative pain and decreased mobility of the shoulder. Discuss it with your orthopedic and plastic surgeons. Best wishes to you!