Sometimes a white solid curd like substance with a bad oder grows have the back of my throat what could that be?

Tonsil stones: Tonsil stones are small bits of food that get caught in your tonsils and then the bacteria in your mouth start to live on the food. If it bothers you, see your doctor.

Tonsil stones: It sounds like you may be describing tonsil stones. You can reduce them by gargling (and spit out) with hydrogen peroxide solution. If they persist, are numerous, cause chronic bad breath or chronic low-grade sore throat, you may be a candidate to have your tonsils removed.