Will running/jogging/walking help me improve the straight cervical curve i have? i'm 23 and suffer constant neck & whole back pain because of it. thx

Yes: A lack of the normal cervical curvature is actually more a sign of chronic neck pain than a cause of it. This means that because the neck continually hurts, you develop the habit of holding it stiffly so it looks abnormally straight on X-rays. In most cases, physical therapy is the best way to address this which will include specific neck exercises as well as general wellness and exercise.