I have had severe lower back pain for approx 1 month now. I have seen my MD numerous times. He thought that I pulled a muscle. I did not do anything physical to have pulled a muscle. I have had an X-RAY, CT SCAN and a MRI of my lower spine. The MRI showed the following: 1) multiple gallstones virtually filling the visualized portion of the neck of the gallbladder, peri-cholecystic fluid detected on the margin of the images. 2) There is a 3.8 cm cyst in the anterior aspect of the right kidney, which is almost certain a simple cyst but is incompletely caracterized on this exam. 3) Moderate degeneration of the intervertebral disk with mild bulging and a posterior midline tear. 4) Mild degenerative facet arthrosis at L 4-5 and on the left at L 3-4. Which of these findings is most likely the cause of my lower back pain? Or, are there more tests needed to determine the cause?