Hello. I have been diagnosed with gastroparesis, failure to thrive, and functional abdominal pain syndrome. I've been experiencing pain in my back where my doctors sometimes check and say it's to check if my kidney's were working or something like that, and just today I saw my urine was discolored. It was brown, like cola, and I hadn't been doing any excersize or eating anything different than whats on my diet. I also found a strange quarter sized lump on my head just behind my right ear, that is squishy and yet firm to the touch. It moves when I push on it, and is the only spot on my head I can feel my heart beat. My friend told me he had a girlfriend who had something exactly to that description, and it turned out to be a brain tumor. He asked me if the lump hurt when I bent over, and it did. Is it possible that my kidney's are failing, as well as the brain tumor?