My baby spunky has been really weird, he's gained lots of weight very quickly over the past few months and his hind legs and back are very sensitive. He recently started screaming in the middle of the night (not wheeking but actually screaming like he was in pain) scared me so bad. After an hour my boyfriend figured out he was screaming for food. He's been doing this and we try to ignore him because he has a pretty constant food supply but he won't stop screaming for hours at a time if you don't give him more food then he eats it all down really fast and does it again. We have tried not to reward this behavior but I'm getting really worried. Recently he has also gotten a small bump on his back its not a scab or a pimple like thing more like a mole? My other guinea pig always gets worried and tries to comfort him when he's screaming for food. Haven't heard him do this since I first got him as a baby and he had some tummy aches and mites. What could this be?