How can I cure neck pain forever?

Hard to say. Much depends on the cause of this pain, anying from acupuncture, physical therapy, postural correction or even for some cases surgery may help.
Maybe or maybe not. This really depends on the source of your neck pain and whether it can be just managed versus cured. You need an evaluation by a spine specialist for this answer to get a diagnosis and treatment recommendations and options with the risks and benefits of the treatments available and their success rate based on your own medical condition and diagnosis.