When this happens is your phone hot as it could be a safety feature which will close down said app to self protect from overheating - However that been said a warning saying so normally appears
No..its not hot..I think its not normal...im not able to watch a full movie? Those this device really that easily get hot? What can I do to avoid it.. Do you think its virus?
Boot on safe mode and see if you get the dame result, if you don't then it's a third-party app acting up, perhaps a battery app, Antivirus, taskillers, etc