Is there such as thing as sciatica?

Back & Leg Pain. Sciatica is pain in the distribution of the leg as a result of an irritated nerve or facet joints or other injury typically in the lumbar spine (low back) which are caused by herniated disks, spinal stenosis or degenerative disc disease, etc requiring further evaluation by a spine specialist and may be candidate for facet injections/radiofrequency ablation and epidural steroid injection.
Yes. The sciatic nerve runs from the buttocks to the foot, in the back of the leg. Inflammation of this nerve, usually from a herniated disk, causes sciatica. The pain can be quite intense, but usually get better with treatment. Physical therapy, oral and injectable steroids are typical treatments. Sometimes surgery is necessary to relieve symptoms.
Yes. Sciatica is a layman term meaning pain that travels down the back of the leg. There are many possible causes. It is almost never caused by damage to the sciatic nerve.