Your mention of the norovirus is perhaps important in your diagnosis. However, for some reason, your doctors have chosen a course of action in their treatment that does not address a possible immune response. Tramadol is an opioid, and Flexeril is a muscle relaxant. They are focusing upon muscular and perhaps vertebral involvement.
If, indeed, your CNS has become irritated and inflamed as a result of the infection (a symptom which those with autoimmune headaches are familiar), about the only medication to break the headache is a triptan, which acts as a vasoconstrictor. Triptans are often highly specific amongst individuals, with some working better than others. Out of the several I have tried, I get the most satisfactory results from naratriptan. On the downside, it doesn't start working until about the three-hour mark, with full effect at six hours, but in my case, it lasts almost 48 hours. But it is effective at a dose of 2.5mg, a fraction of the dose of others. Zolmitriptan is another good one, at 5mg -- faster acting but shorter lived. (Don't drive a car for the first few hours of zolmitriptan.) By comparison, sumatriptan, the most commonly-prescribed, is usually given in a 50mg dose.
Your body actually has two immune systems. One, housed in the gut, is highly sophisticated in fighting infection. The second in the CNS is very primitive and rudimentary, and once the CNS becomes activated, it is like swatting a fly with a shovel. Also, when an infection or irritant (such as a chemical toxin) has been present over a length of time, the CNS can remain in an inflammatory state longer than is safe for it to be so. The pain experienced under such a condition is actually from nerves and tissue pressing against the inside of the skull, or overall compression in tight spaces. This is where the vasoconstrictor is helpful.