Yes, karma is simply the law of causation. Just a small quibble -- Brahman is not a substance composed of anything. Brahman literally is existence-consciousness-bliss that can be described as reality, knowledge, infinity (Satyam Jnanam Anantam). Thus, God is not made of anything, but all is made of God. There is also a clear parallel with Abrahamic God, who goes by the name "I AM" (consciousness-existence) and is also equated with love (bliss). In that (Judaic) context you certainly can talk about (self-inflicted) suffering as punishment, etc.