In my San Francisco area practice we perform autologous and implant reconstructions.
Breast implant reconstructions typically need to be performed in stages. The first stage is the placement of a tissue expander that has a much thicker shell and a specialized port designed to allow injections to expand the implant over time.
This expansion stretches your skin, subcutaneous tissue and pectoralis muscle (if the expander was placed under the muscle - which is typical).
Expansion is performed usually in the office and is a quick 10 minute procedure. The feeling of a slight tightness is used by a guide as to when to stop the expansion. It should not be painful. Most patients can tolerate about 60 - 100 cc per expansion. Typically this number is larger as time goes on. It is important to remember that some patients may tolerate significantly more or less.
Patients will also notice that tissue expanders are significantly more firm than normal implants and some adjustment may need to be made in terms of placement.
Any time you have post-operative concerns be sure to discuss these with your surgeon.
I hope this helps.