Back of the head to the left. Pain. What's going on?

The most common cause of pain is herpes virus infection, herpes virus is a neurovirus, can cause neuralgia, rash, blisters. In some cases, the virulence of the virus is relatively weak, and the human resistance is relatively strong, only pain, no blisters, no erythema, easy misdiagnosis; second, there is also a case of cervical spondylosis, which may be disc herniation, may be spinal cord lesions, and may be tumor compression to other nerve roots, which may cause pain in the back of the head. In addition, excessive muscle tension in the neck can also cause pain, which is more common in stiff neck, muscle strain caused by improper posture, neck ankylosing fasciitis caused by watching computer for a long time, watching mobile phone or writing, can cause pain in the back of the head.