Piriformis syndrome is pain and numbness in your buttocks and down the back of your leg. It occurs when the piriformis muscle in the buttocks presses on the sciatic nerve.| medlineplus.gov
Sciatica refers to pain, weakness, numbness, or tingling in the leg. It is caused by injury to or pressure on the sciatic nerve. Sciatica is a symptom of a medical problem. It is not a medical condition| medlineplus.gov
A herniated or slipped disc means that one of the soft cushions or discs between your vertebrae or spinal bones pushes out. Find out about it here.| medlineplus.gov
Lumbago is pain on the lower part of your back. Back pain is very common. Treatment varies from medicines to surgery depending on the cause and kind of pain.| medlineplus.gov