Dear Pain on back of skull located only on one side is likely to be due to occipital neuralgia. This pain is produced by compression on lesser or greater occipital nerves which can be produced by a number of causes. You will need to see a doctor preferably a pain management doctor who can give a diagnostic block and pain relief with a diagnostic block confirms the diagnosis. Certain medicines like anti depressants can be used to medically treat the condition. Steroid injections may also be used if medicines are ineffective.