Finally a pain diagnosis--but how can I get ADHD wife to tone down the stress?

For years, we have been going to doctors and ERs because our 13-year-old (with ADHD and lots of other issues) complained of severe pain, only to be told that they could not find anything wrong.  Our new pediatrician said we should see a pediatric rheumatologist.  After an hour and a half of probing and asking questions, she said that it is Amplified Muscular-Skeletal Pain Syndrome (AMPS).  She specifically said that it is caused by stress.  She also said some kids with the condition couldn't even go to school because the pain is so bad.  Treatment includes regular exercise, massaging areas with pain, reducing stress/anxiety, and establishing a better sleep schedule.

Those of you who have read my previous posts will know that the 13-year-old and my ADHD wife often get into a feedback loop of anger.  I tried to explain to my wife that yelling at them will make the pain worse, which will cause them to freak out more and thus increase the pain and thus cause them to freak out more.  I explained that things that might work on most kids will not work on them, especially since we know about this pain/anxiety feedback loop.  I reiterated what everyone has previously told us - say something calmly once and the only person you can control is your self.  My wife comes back with the "don't I have a right to get angry" and stressing the fact that they did something wrong (not cleaning room, making a mess in the kitchen).  I explained that yelling at them won't get them to clean their room.  I asked if it would be helpful if I yelled at my wife about the sink full of dirty dishes.  I also explained how I had made the decision not to respond it kind to my wife's anger and that it saved our marriage.

She goes back to the "you are saying I am broken" because of ADHD argument. 

On a positive note, my wife has finally started taking ADHD medication.  She does not, however,  have a therapist and we have not been able to work with the county-provided parenting coach for a few months because the authorization expired.