Hard stomach

Carly
My stomach often gets very hard and firm all over, if I'm laying down or sitting. There isn't any pain but it's weird and not all that comfortable, however it goes away after a few moments. I've read and heard that the only time your stomach should ever get hard is if you're contracting- but I've been having this happen my entire pregnancy! Even in the first trimester. I asked my doctor about my stomach getting hard, and he said he didn't know why but everything was okay. Does anyone have any opinions? I just want to know what it is! If it is Braxton hicks, why have I been getting them my whole pregnancy? It worries me sometimes. Thanks!