What kind of specialist should I see about siatica I suspect I got herniated disc chiropractor or spine doctor? What one if best to get MRI through?

If you have. symptoms of a herniated disk with radiculopathy(sciatica) you should probably be evaluated by a spine specialist, which could be a neurosurgeon or orthopedic surgeon.
Sciatica. Please start w/your family doc. He/she may refer you to a specialist. Once you have a clear diagnosis you can decide on one of the options these docs recommend and discuss chiropractic care w/them also. Natural and non-invasive treatments can be very effective. Surgery has mixed results. See the work of John Sarno, MD, about a psychological way to deal w/pain after diagnosis and talking w/doc.