How to resolve once and for all severe neck pain?

Neck pain. Only after proper diagnosis following a thorough musculoskeletal/neurological exam will proper treatment be effective. Not all treatment for 'neck pain' is the same. The cause of the pain needs to be diagnosed to guide appropriate treatment ( whether it be physical therapy, injection treatment, medications or surgery). Good luck.
McKenzie Exercises. Pt for back and neck conditions involve stretching, strengthening, and some range of motion. These exercises start very gently, and then are progressed by a certified pt based upon patient response. All patients are different, so the exact exercises differ as does the progress. Use of heat, rubs, electrical devices and ultrasound is not a long-term answer. No pain no gain to a point.