I have a pain in the back of my head it's on the left side just right above my neck it feels like a strain and it's been 4 days now, the pain med dnt?

A headache lasting : That long not relieved by pain meds deserves a medical visit.

Headaches/Neck probs: Soreness in this region could suggest muscle strain or tension headache. Any problem causing muscle tension may create headache. Greater occipital neuralgia can also be a cause. Maybe see a neurologist and be evaluated. If all clear, then pursue cervical treatment. Robin mckenzie book "treat your own neck" is $8.32 online, otc meds, injections if all else fails.