yeah this is my second pregnancy too, and my Dr. told me that its because our bodies have already grown like this before. we tend to grow faster and it can put more pressure on ligaments and muscles. if its pure pressure, maybe your carrying differently then last time, perhaps much lower down then before? i've had several odd pains and pressure spots but they do away if i change position of stretch a bit. all she told me to help with the tightness is tummy massage and drink lotsa water. good luck, hope it helps!