Is Arthrotec (diclofenac and misoprostol) better than Meloxicam for arthritis and back pain?

Somewhat different. Meloxicam is a non-steroidal anti-inflammatory drug that taken long term may require a proton pump inhibitor such as prilosec to prevent G. I. Problems such as ulcer. Arthrotec (diclofenac and misoprostol) contains diclofenac, also an N SAID but also misoprostil an older drug to protect the G.I. tract. You should try diclofenac separately without and Mexican to see which is better. Long term u need pump inhibitor separately.
Not necessarily. Both are non steroidal anti-inflammatory drugs and one may work better than the other for different individuals. Try to get samples of both from your doctor and try one for a week to 10 days, then the other before getting a prescription if possible.