Hi! Welcome to the board!!! Wow, canker soars...ouch! Which tests have you had done (I know you mentioned you've had tons of testing done)? I'm not so sure that canker soars from bread is normal...could you have an allergy to something you're eating? Did you always get soars from these foods or is this something new? Have you noticed other symptoms like itching or spots on your skin? I'm sure Heather can give you some ideas as to what might be going on...I'm just concerned that there might be somehting else to consider?
I agree with everyone else's comments...I would try rice as a starter. See how that does for you. Also, there's something out there called Quinoa, you might look into that (it's lower in carbs I believe).
I wish you lotsa luck! I hope you're feeling better soon! Keep posting! (((hugs)))