Dr. Tajunnisa M
Hi Nikhitha. Such change in the behaviour could have happened due to separation anxiety. Growling could be a reason due to pain or discomfort. Gastric upset post boarding is not uncommon ( A strict advise not to change diet to the concerned person is necessary). Overall, considering his behavioural changes, I would suggest you to either speak to a vet online or get him thoroughly examined by a vet on kuddle.