Woah, kinda... forgot about this thread, oops. SORRY!
I have a 'strong' seat/position, if I concentrate on it- but I do have the hip problem that is just barely noticable, and most of the falls I've taken I've landed flat on my back, I've probably messed something up.
Just now I was leaning forward on the computer desk to read through all these posts, and after a few minutes of that my back/shoulders area is killing me.
I was actually considering a yoga-like class anyway, so now I'm going to look into it seriously, and attempt to get checked out- my parents don't see a problem though, they're very against going to the doctor for 'silly little things', but I'll see what I can do and find some classes!