It is always better to start your own new thread than to piggyback onto another as the questions I answer sometimes get confusing with multiple individuals on one thread.
Lower back pain at 30 years old is not unusual. The X-ray reading is not too thorough. There is no comment on alignment, disc height, angulation or other findings that might explain your symptoms.
Lower back pain at your age could be from pars fractures (isthmic spondylolisthesis), degenerative disc disease, degenerative spondylolisthesis or even facet disorders. See the website for further descriptions of those disorders.
If your pain has been present for six months or is disabling, you would be a candidate for an MRI. This imaging study is the gold standard for understanding the causes of lower back pain.