Get Sambucol, an anti-viral over-the-counter medicine (at convenience stores, pharmacies and natural food stores), or else get elderberry tea in the bulk section at your local natural food store. It will look like dried little dark berries. Just put into boiling water and steep for 10 minutes, and give it to him about 3x/day. It's kind of sweet, so he shouldn't mind; otherwise, you can add a little stevia. Elderberry is an anti-viral and will help to ease the headache and to make it pass sooner.
Get your son a good mushroom complex, too, and a good, multi-strain probiotic supplement. Both are excellent for his immune system.
You can also take him to an acupuncturist, and have the acupuncturist treat him for pain relief *and* to boost his immune system so that he will get better sooner.
Once he's feeling up to it, have him gargle with very warm salt water - as warm as he can comfortably take - several times a day.
I'm a little concerned about this headache. I've never heard of a virus-induced headache. I encourage you to look it up online and see if there's any chance that it's a form of meningitis - just to be sure. Doctors really just don't seem to know anything anymore, and I wouldn't leave it up to the doctor to decide that everything's ok involving my child's brain.
But assuming that he is safe and it's just like the doctor says, you don't have to wait this out and suffer through it at all. Follow my advice and your son will be feeling better within hours.
Now, go look up an acupuncturist! You will be so glad you did. It won't be a miracle cure but it sure will help a lot. On the way there, get those supplements. Your son will be feeling better by the end of today.
L.