Extreme headache on the left side (above ear). Just started 5 days ago. Doc tried muscle relaxers-didnt work. Codeine barely helps. What could it be? -

Simple Injection. Occipital nerve injections are simple to perform, low risk and very readily identify these headaches(occipital neuralgia).These injections are performed by some neurologists, and almost all pain specialists(don't let them talk you into an epidural). If it's occipital neuralgia, you will have pretty complete relief in 10 to 20 minutes. Injections might need to be repeated. Findout why your having.
Headache. Migraine headache is frequently in one side, but apparently is new in you, with out probably migraine hx.That probably is a occipital migraine, tensional or related to ear problem, .Check any ear infection, neuralgic pain, vascular headache. Some times Motrin 800 mugs help, but recheck with your pcp before to take any meds.
Other causes. Need to go into details of headache. Other possibilities are status migraine, hemicrania continua, sinusitis or eent problem etc.