Before considering that it's "sympathy pains" ... I'd likely take him to the doctor, tell the doctor about
your shared symptoms...and see if there isn't something environmental going on, that's affecting both of you. Low levels of carbon monoxide? Radon? Something in your drinking water (do you have your own well, for example)? Something that you're both allergic to, in your house? some chemicals you use regularly for cleaning, or painting? Some other way that you are both being poisoned by something you are sharing?