I have had a headache for several days which seems
Please see the detailed answer below
I can understand your concern.
As per your history, as you're already having degenerative disc disease with fusion at cervical spine level, headache may be due to occipital neuralgia. It develops due to pressure or irritation of occipital nerves.
I will suggest you do an MRI of the cervical spine after a Neurosurgeon's opinion. For pain, you can take tablet Naprosyn 250 mg twice a day.
Along with that you can use diclofenac ointment, use heat pads and cervical collar and do regular physiotherapy.
If you are not getting relief by all these conservative methods, then surgical options like microvascular decompression surgery are available. Kindly consult with the Neurosurgeon for detailed examination and evaluation.
Hope I have answered your query.
Let me know if I can assist you further.
Dr. Shyam Kale