I've had my tonsils removed twice already but stones are still coming up from behind my tongue, down in my throat. My breath smells bad all the time.

See your doctor. If your tonsils have been removed, i would recommend a follow up visit with your physician or ENT to ensure all tonsilar tissue has been removed, and to check for any abnormalities of the throat and esophagus, such as a weak esophageal sphincter. The 'stones' could be food particles working their way back up due to problems with the muscles of your esophagus.
Tonsil stones. You may still have fissures that are trapping food and other material. See your physician to determine if this is the case.