Hello
Low back ache may be due to many reasons like genito-urinary causes,pelvic causes,musculoskeletal reasons etc.
You need proper clinical examination and routine investigations.
Investigations include routine hemogram,random blood sugar,
liver function test,renal function test,urine RE/ME,
ultrasound of abdomen,X-ray L/S spine (AP/Lateral view),
Thyroid profile,serum calcium and vitamin D level.
It may also be due to low calcium level or muscle spasm.
MRI of L/S spine can be done after evaluation.
Proper treatment depend upon findings.
Get well soon.
Take Care
Dr.Indu Bhushan