The dual diagnosis of tics and ADHD is indeed difficult to deal with.

Since the tics worsen along with inflammation, perhaps targeting that might be of benefit? I know this sounds out in left field, but perhaps information pertaining to fibromyalgia (targeting inflammation) might be useful? Also, you might refer to a book by Kenneth Bock, M.D. titled "Healing the New Childhood Epidemics: Autism, ADHD, Asthma, and Allergies."

My family member as a child also had tics (TS) and ADHD but the ADHD turned out to be a misdiagnosis. That is different from your son's case. However, I do understand the painful tics.