When you go in for x-rays, be sure to ask for the merchant, or sunrise, views of your knees. These are a series of x-rays taken with your knees bent at different angles (mine were 30, 60, and 90 degrees). This is the best way to show patellar tracking and/or tilt within the groove. Don't be afraid to speak up and specifically ask what types of x-rays you will be getting, and requesting those views.
Your next step would be to find an orthopedist who is a knee specialist, and preferably a patellofemoral specialist. Unfortunately, a lot of general orthopedic surgeons just don't know enough about the mechanics of kneecaps to handle your situation well (I'm speaking from a lot of experience, and just about anyone on the patellofemoral forum here can say the same thing). Your best bet is to ask around and get a recommendation for a PF specialist... ask your doctors, orthopedic surgeons, and physical therapists, who usually have a very good line on who the best physicians are for particular problems.
You could also post to the Patellofemoral Forum here at KG... there are dozens of us there who all have kneecap problems, so you'd be in good company

Andi