my chinchilla keeps yelling

hey everyone so i got teddy in march 2017 and he was fine he was a rescue and hes 4 years old, for the last like 2 months hes been doing this thing where he pops his head foreward and starts making this like yelling noise and he only stops when i go give him attention or speak as soon as it goes quiet he starts yelling again untill i respond its quite worrying is this normal? is he too spoilt maybe and trying to have all my attention? i do give him a lot of attention and toys hes already had 2 new cages since i got him but he is alone with no other friend but me as im not sure how well he'd respond to being with another chin as he was alone when he was up for adoption. could he maybe have some ptsd from before? thanks <3