Have hard neck pain for 4 months now, and intense shoulder pain with a popping sound on movement, now arm weakness with side breast pain 4 a minute?

Neck,shoulder: The problem could be a bulging disk in your neck causing radiation of discomfort toward the shoulder. This could also result in arm weakness. Of course there could also be a concomitant shoulder disorder like tendonitis or arthritis. These would be affected by motions of your shoulder itself. If the neck us the primary problem, consult a neurologist or neurosurgeon for evaluation and testing.