What to do if I have really bad sinus headache/migraine took the sinus relief and didn't help much at all can I take diclofenac?

ENT doctor. If the pain is refractory to the sinus medications which are designed to decrease the inflammation in the sinuses and thus the pressure, you may want to consult with an ENT doctor. Sometimes patients may need some "extra help" in clearing the sinuses and the ENT doctors may help by surgically removing collections. Also an MRI or ct scan may be done to make sure there isn't some other cause.