I have the exact same thing, except I don't faint. Instead, I get horribly dizzy, extremely nauseous, and faint in the sense that I feel weak and shaky. I am not sure, but now, thinking thorough it, I think its because the first time I changed my earrings, it hurt, because the woman who had pierced them, had done it slightly crooked, so the hole was not straight. Now the very thought of even pulling my earrings out is terrifying, and I feel sick at the thought. What I am doing though, is the Ten Steps. You slowly start out with anything that reminds you of changing earrings. Like maybe watching somebody else, or seeing just a picture, depending on how scared you are. then you might touch you ears, one at a time, for a minute or two. After that, step three, you might twist them around once. Every single step you have to do until its "second nature" feel, and you are completely comfortable. Don't be impatient, and skip ahead. If you want an idea of about how far it goes, step 8 or 9 would be changing someone elses earrings for them.
I really hope this helps.
Sounds almost like a self-learned behavior.
I am sure when you got your ears pierced there was pain and discomfort associated with it. Especially in the first stages when the hole is not yet closed.
Sounds like your mind latched onto this, and is associating pain and discomfort with ears, building into some kind of fear and anxiety.
This might be resolved by you desensitizing yourself, either through hypnosis, or "good thoughts" when you play with or put your earrings in.
Just a thought.
My sister used to be like that with her belly-bar.
She couldn't touch it or bear to have it changed without fainting.
To be honest i thought it was just a fear that had gotten exreme, as she's scared of needles (faints at the sight and touch).
She seems fine now though. Maybe it's a fear?
You may want to read this: http://heartdisease.about.com/cs/arrhythmias/a/Syncope2_2.htm
Some people faint at the sight of blood. I would talk to your doctor about this.