<s>[INST] For almost 5 weeks now I have had lower back pain -- where the spine ends at the pelvis.  I went to see a GP and he tested my urine (normal) and had lumbar spine xray (results not in yet).  I have been taking 850mg ibuprofen 2x a day, which helps but one day when I stopped (because I felt better), the back ache returned.  I'm now feeling some kind of fatigue sensation down both legs.  I also had constipation problem recently -- more often than normal.  I'm 63 but otherwise healthy -- no health problems until now.  Should I see a specialist -- what kind? [/INST] Hi welcome to HcmYour symptoms are suggestive of lumbar spondylolisthesis.Get MRI total spine and review with reports.Drugs like pregabalin well help.thankyou </s>