Oh yes! Many! With lots of possible variables.
The main cause is fairly simple, but what to do about it, and how to make it better rather than worse is a little more complex. Almost everyone is bound up to their other side, and have lots of imbalances. The body is fairly simple, just make all the weight go through the joints, and not get cut off. The muscles just bull themselves tightly on to the bone, in order to maintain structural integrity, as it were. So all that is important is keeping form, basically. Only, when you're all fucked up, as most of us are, you gots to take some drastic measures.
People can hold great postures standing up, but then when they bend over, they lean over, and hinge their weight at the hips in one of many ways. This hinging lengthens some muscles, and contracts others. A big one, which is what I did, was basically lift the opposing leg you're leaning over with. I'm all fucked up in all kinds of ways, but like, I said, I'm more sink or swim measures. See, all of that yoga has gave me pretty good physical awareness, and I can feel the tension, and places where things are bound up, so's that I just force a release, and see what happens. When you start to lengthen one side too much, and shorten the other one too much, you'll start to flex muscles in your neck, mainly, to hold the weight from hurting you, basically, from pulling too much on a nerve, probably for that reason, I figure. So, that giving me more movement between my shoulder blades, and widening my shoulders (people have told me that I'm getting thinner, but I've actually put on like fifteen pounds) also widened my lower back quickly.
Then, if I can't contain my lower abdomen, then that puts too much work on the lower back, which now has more movement range than it probably ought to. I sleep on my stomach, and like eating a lot and I'll lose structural integrity in my lower right ribs, and under my left bottom shoulder blade, and that combined with containing my core less cause I'm all stuffed, all makes my lower back contract too much when I'm sleeping... something like that...