Should Reconstruction Expanders Move Under the Skin?

Tissue expanders are typically textured, specifically to prevent movement.  However, anytime a pocket is made, there is the potential for movement.  It is unclear from your message whether it is the expander that is moving, or the stable expander that is causing pain.  You should have your operating surgeon evaluate you and consider an ultrasound to determine if you have a seroma around the expander.

Movement of tissue expanders within the surgical implant pocket is not necessarily uncommon. If it occurs it is usually a rotation issue where the more projecting aspect of the expander moves to a different location, creating an asymmetry in breast appearance. The fill ports will then be in completely different locations during subsequent expansion. This can happen with a textured device. Your description suggests that you may have a seroma, or fluid around the expander, which could allow more implant movement. From your time frame it appears you are ready for an implant exchange, at  which point a seroma is evacuated. Some discomfort on the other breast is also possible due to the general stretching of tissues by the expander. Also, a capsular contracture around the implant can produce symptoms. In any case, this is addressed during exchange with your permanent implants. It's always a good idea to have your surgeon assess the situation.

Tissue expanders can move in their pockets under the breast skin. We go through great lengths to prevent this, by anchoring the expanders in place with sutures and using textured expanders. If it is moving, (1) have your surgeon examine you to be sure you do not have a seroma/collection of fluid creating space around the expander. (2) Putting more fluid in the expander can make the expander fit more snugly under your breast skin and keep it from moving so easily.