Pain in back and pain in leg this could be related to each other or it could be separate issues also.
You can check one thing lying position on your back legs straight. Now when you lift your leg up straight ( any one leg ) then how is your pain in leg and back. If you say pain is more in back and at the same time in leg also then it can be associated to each other and you have problem at limbosacral spinal level. Now if there is pain only at back and there is no pain in leg follow the another test.
Long sitting position that is sitting only but keeping your leg straight ask some one to hold your calf muscle bulk and squeeze it or press it hard and check do you have pain in leg. If you say yes then it can be due to problem with blood circulation in legs.
How ever the conformation can be done by only specialist like ortho or physio and you may need to under go for
MRI of back as well dopler study for legs if needed.
And based on result of physical examination and MRI ortho doctor for mild to moderate issue will suggest to take
physiotherapy treatment and exercises along with medication. For major damage at spinal level he will suggest for needed surgical correction.
Now if there is circulation problem in lower limb here doctor may ask you to visit a vascular surgeon or some medications again for it.
Doing exercises suggested by physio for
back pain radiating to legs along with use of hot and
cold pack at back also gives good relief.
Take care.