Tender Sensitive Teeth from Invisalign Retainers?

Orthodontic research has shown that orthodontically treated teeth will need 7 months for the periodontal ligament fibers and bone to fully remodel. Thus, in our practice, we ask our patients to wear their retainers one year full time (we over do it...), then to bed lifetime.

Thus, I think your reasoning is correct, your teeth may be moving slightly during the day, and then you are moving them back into position when you wear your retainers.

Dear patient,
There is no way the retainers can make your teeth sensitive, unless you developed gum recession during the treatment or you had gum recession to begin with.
Hope this answered your question.
Dr. Barba

I think you may be on the right track, that your teeth move during the day when not wearing retainers.  It is curious that it has started 4 months after completion, though, so you should certainly consult your dentist to rule out other issues.  There may be a bite interference that needs to be adjusted.