How to find out which inactive ingredients in drugs i am allergic to. i get terrible headaches and pain behind my left ear when i take certain meds. ?

Several options: List all the meds you have that reaction to. Then do not take them! second look to see if there is a common ingredient or two in all of them. That helps narrow the field. Consider seeing an allergist. Look for other ways to manage your symptoms. Homeopathy, acupuncture, and chinese medicine can really help...And then you may not need the meds.

Seek the pattern: The most accurate, and more reliable test for allergy to a substance you might eat is to see if you get a reaction when you ingest it. This is only an option if your reaction is not serious or potentially serious. If your reaction is headache and discomfort, then see if you get the reaction every time you ingest the inactive ingredient and not at other times.