Hi Kim!
I've had my expanders in for quite a while now (I'm in limbo cause I had a recurrence and am dying to get started again!)
Originally when I started reconstruction for the 2nd time cause my first attempt failed, I decided to have my other breast removed so I could have a matching pair (at the time I was told I could only get an implant.) Now after going through one set of smaller expanders and telling my doc that they weren't big enough, he told me that he'd also take some tissue from other areas to help build them up. I currently have one expander that is nice and soft and very natural - the other has some dead hard tissue in it and I hate it. It's uncomfortable and hard - but I know my doc will clean it up we we are allowed to move forward (I just completed radiation and I'm contemplating chemo.)
Before I would go in for a fill I would take some Advil or something and it would help with the discomfort a bit, but the next several days I would feel "tight" but nothing too bad. It sounds like perhaps he put too much saline in. For some weekly fills are ok, and others need more time between them. My soft breast doesn't ever hurt after a fill, but the hard one does. So if your pain level doesn't go down, I would talk to your doctor again. He may put off your next fill.
As for the diff between the flap side and the expander - well you will always have a bit of a difference. Your flap will grow with your body as you gain weight or shrink if you lose any cause it is your own tissue. An implant cannot do that. Of course your doc will try his best to achieve symmetry and should get close, but there may remain minor differences. If your implant is done right you can have a nice soft natural looking breast instead of something that resembles a melon.
My advice would be to stay on the muscle relaxers and take something mild for pain (tylenol, etc.) try ice packs or heating pads on the "pulled" muscle. It should start to ease up in about a week. If it doesn't consult with your doctor.
Best of luck!
Angi
Oh and sorry it took me a bit to get to you. I'm dealing with Hurricane Gustav aftermath (lots of debris to clean up) and prepping for Hurricane Ike!