I had this hun, and wrote a post about it and other girls said they had had the same thing.
It felt horrible, moving around like the implant was too small for the boob house lol. Mine also kinda hurt when I moved about, lifted my arm, or used my left arm for anything. My right boob settled and dropped really quickly (prob cos i am right handed) and I didn’t feel anything strange in my right at all. I even phone the nurse about it who said it sounded normal and would settle down and she was right. I think I had the swishing for about a week, but also had shooting pains in the left and now the left is spitting stitches – problem child ha ha. No more swishing though 🙂 xxx