are you sure rotation lock is off? have you tried to do a restore? if those don't work, then there is a possibility your phone's acceleromter is broken (or whatever the sensor is to detect the orientation of your device)
are you sure rotation lock is off? have you tried to do a restore? if those don't work, then there is a possibility your phone's acceleromter is broken (or whatever the sensor is to detect the orientation of your device)