How do I know if my pain is a sciatic nerve or something more serious?

Need MRI. If you are concerned, i would consider asking your physician to order you an MRI to evaluate your spine.
See doctor. for an evaluation and possible testing such as a MRI.
10,000 causes. First diagnostic test is a lumbar mri.Ri will determine if your pain radiating to the back of your thigh, buttock, and leg is originating from a bulging, herniated , or degenerative disc problem, arthritis of the spine, articulating facet problem versus masseuses , cysts, colon, spleen, liver, gallbladder, pancreatic, or 10, 000 other reasons for sciatica and lower back pain.
More symptoms. Sciatic pain has certain characteristics such as pain along a nerve distribution, numbness, weakness of specific muscles. Some of these symtomps can overlap with diseases of kidney, hip, abdomenoo your doctor can help you sort out your symptoms.