I have had off and on pains all through my middle since the beginning. In the first 3 months it was mainly mild menstral like cramps, sharp pains in/around my ovaries, and then severe sharp pains when I changed positions due to the stretching ligaments.
Now that I am about 6 months along and my uterus is the size of a soccer ball, the pains come from my growing uterus and baby movements pushing my organs further up into my rib cavity. The baby also has a bad habit of hitting my cervix, causing a feeling of pressure, and sometimes a pins and needles feeling.
Those two growing things, baby and uterus, are also causing my acid reflux to worsen as they put pressure on my stomach. Gas pains before pregnancy were sometimes really bad, causing major double over cramps, but they are even worse now since all of those organs are pushed up into my rib cavity.
I have also had occasional sharp severe pains upon going to the bathroom. The only thing I can figure on that one is when my bladder is full it stretches my muscles out even more, pushing the baby in a different position, and then when I go and my bladder shrinks back down, the muscles shrink back into place again, and the baby's position changes, causing pain.