AvatarNathan Richer

have you lain down on the ground and had a PT or someone look at your leg lengths? you can get that done before going for Xray. 

and if you find you have leg length discrepancy, i would also see if it is fixable by adjustment of the spine or pelvis.  readjusting your pelvis can also fix leg length problems. see: http://www.youtube.com/watch?v=INBY84sqrR0
if it is fixable via manipulation, then your leg length discrepancy is thankfully not structural. if it is structural, then you should see a PT about that. check out what Kefu said previously.