welcome you to healthcare magic forum,
do you have any history of fall ,any other complaints like stiffness
and difficulty in movement early in the morning,family history of back pain?there are some causes of back pain in this age group.it may be simply musculoskeletal pain
from muscle spasm, inflammtory arthritis
or any problem in vertebral colomn.you better do some investigation like x ray of S-I joints,x ray D/l spine and a complete blood count
.it will dictate nature of your back pain.