Why do you only get back contractions?

[BabyB04]

Is it more painful to get only back contractions?

No idea why the back though

Apart from a few period type pains at the very beginning all the pain was in my back and bum. All 3 times. Dc3 gave me lots of pain in my left hip and down my leg and I've been left with period legs since having him where I get more pain in my hips and legs than my stomach. My back has always hurt more. That gas and air couldn't get to my house fast enough!