So what kind of damage do the scans reveal? One thing that is expanded upon by Sarno in his book is that he would scan the backs of normal people off the street as a control group when doing experiments. One of things he noticed was that these "normal" people (they experienced no chronic pain) had just as many physical abnormalities (herniated discs etc) as the chronic pain sufferers did! So I think what he (not me because im not a doctor) would say is: You may very well have had tissue damage in the past which probably healed at some point. So when you get a scan you can still detect where it healed etc. But that does not mean that your pain is anything other that "neuroplastic pain", ie, your body has healed but the "pain" has been remembered!
Wow that is a fascinating remark about daith piercings! I luckily dont suffer from migraines but migraines are another commonly attributed TMS symptom, so since you have that history it may mean you have traits that match the TMS personality...