Had mri of lumber sacral spine, there is a big bright spot on right under what looks like lung/liver . is this significient?

Some questions can't: ...Be answered in an online forum like this. I assume your doctor has sat down with you to discuss the results of your mri? If you can't understand your doctor's explanaiton, or if he/she is unsure, you can always ask for a second opinion, but this is not the place to get one. That needs to be where we can see your mri, and take a history/physical exam.