What do they check for when you get an eye exam?

I want to know because everytime i wear my glasses my right eye starts hurting and i feel like throwing up. I got my glasses about 5months so im used to them. My left eye does not not hurt its my right eye i get headaches and feel like throwing up when ever i wear my glasses. The other glasses i had were fine but then my right eye started hurting same thing with this they were fine at first then my right eye started hurting. I go to the optometrist and he says everything its fine with my glasses but WTF is going on!