I am 5 days into using Invisalign, is this causing my head and ear pain/ache?

Some teeth tenderness and headaches can be expected, since you only started treatment 5 days ago, however ringing in the ears is more indicative of a upper respiratory infection or allergy related clogged sinuses.  I typically recommend that my patients take over-the-counter ibuprofen (if they don't have medical reasons to prohibit NSAID use.  It would be a great idea to contact our dental office and see if your dentist will recommend something for the headaches and teeth tenderness.  Good luck and I hope this helps. Follow me if you have more questions.Sarah Thompson, DMD