Baby shouting at 5 months old

My bb just turned 5 months old this week and recently he started to shout. Like he will tense his throat and 'argghh' and clench his fist. I realise he does this when he is bored, or when he is unable to sleep. It is quite bad and my husband will scold him to get him to stop. He has done this before, at around 3-4months old but it was mild and it stopped after a few days. I'm afraid bb will lose his voice. How do I teach him when he is still so young? Is this normal? He also drank lesser milk recently, like 700ml a day on average.