Many things spring to mind, but assuming that your " friend" is over the age of 65 years, then cervical spondylitis springs immediately to mind. This is a " wear and tear" situation of the cervical spine ( neck) and boney outgrowths ( osteophytes) grow on the bones which may cause a " nagging" pain.
However if these boney outgrowths invade the privacy of nerve roots then the pain changes in character from a nagging pain to " shooting, electric pains " as suggested by my good friend Ratter.
There are of course other causes........but much rarer.