rigid stomach muscle/surgery related?

I'm not talking about my 6pk--lol, long way from that at this point. Does anyone have problems with tight stomach muscles from wls? The center of my stomach is always hard and I can't seem to get it to soften (takes hours of massage) for very long before it tightens up again----it feels like I'm pregnant to give you a sense of how hard the muscles are. Any ideas? Thanks, Katherine