I have lupus with arthritis. am experiencing reduced neck mobility with grinding and popping with all neck movement. should i be concerned?

Yes: Anytime you have a neck mobility problem lasting for more than a few weeks or getting worse, you should consult a spine specialist (usually an orthopedic surgery who specializes in spine). This is true whether you have lupus or not.

See details: The cervical spine pain is secondary to osteoarthritis and not related to lupus. X rays and physical therapy are usually all you need.