I have decided to post about this because I have been using it for over a week 24/7... I came down with a severe bronchitis and had to stop the endless coughing.

The last time I was sick with a virus a few years ago, I had terrible burning. (for 3 days). So I was waiting for the burning this time, but it never happened. I had a high fever one day, and low fever for 2 more, and endless endless terrible coughing.

I've been taking guaifenesin with DM all the time, and I have to say, my feet are feeling almost normal! I had a terrible pain flare around New Year's from some Chinese food that must have slipped me MSG. That is not only GONE, but the other minor discomforts I have typically in my feet are gone also.

Dextromethorphan is the dextro isomer of the narcotic levorphanol, which is a CII narcotic for pain.
DM is over the counter, but carefully sold now because kids are using it to create a high (called a dissociative high) and abuse it.
But you can still find it. Robitussin DM, Delsym, Mucinex DM. etc and some generics are in many stores.

Nide44 (Bob) here has tried high dose DM with a doctor's care.
I think it was at least 100mg/cap..made for that study.
If I remember correctly, it did not work for him.
The OTC doses are 10mg in 5ml of Robitussin DM, 30mg in 12 hr Delsym/5ml dose, or 30mg in 12 hr long acting Mucinex DM, or 20mg in generic guaifenesin DM tablets (which I am using).

DM is a NMDA antagonist, and works on those pain receptors.
So it does have a minor effect on pain.

I just can't recall ever using so much of it for my coughing before. My cat actually had this sneezing/coughing a couple of days before it started on me. She sneezed once in my face in fact. So I don't know exactly what virus I have...I don't think it is the "flu"...and I have no infection...just endless phlegm.
It has been a week now, and my feet are totally, normal at night. So I am going to continue with the DM and see if it continues to reduce my minor burning/pain issues.

Usually when I get sick, my feet hurt MORE, not LESS. So I am thinking it is the DM. I only took pain relievers for 3 days, Aleve liquigels alternating with Tylenol every 4 hours. That was for the fever. I haven't used any for several days now. So it is not them working on me.

Here is a Wiki article about it:
http://en.wikipedia.org/wiki/Dextromethorphan

Notice you CANNOT use DM safely if you use SSRI antidepressants, and this includes Cymbalta. It also has a warning with MAO inhibitors.