Are you using an supplements? Even organic foods are deficient in minerals, which is the key determinant of pH.
Are you undergoing any health issues? Health conditions and pathogens can utilize a good portion of the bodies mineral supply.
Have you ever tried betaine HCL? Many vegetarians are deficient in calcium and other alkaline minerals because they are lacking in HCL in their stomach.
Hidden infections also keep the body acidic. This can be the crux of the problem for many people.
I would advise you to listen to Dr. Marshall's free radio program at http://www.healthline.cc
He streams his program everyday, and he has a great deal of specific advice about balancing pH.
Raw foods are no guarantee for having a balanced pH if one has infection, digestive problems, mental stress, or mineral deficiencies.
Allergies can also enter the spectrum.