In pain passing gas

Hello- my baby has always been really gassy and has had lots of healthy yellow- mustard seed poos. However, this last week (3-4 weeks) his poo is still yellow but not much mustard seeds- more like plain goo with a little mucus. He is also SCREAMINg when he goes to pass gas or do a poo in the middle

Of the night.

I have tried given him gripe water and infacol. I’m already “mainly” dairy free. I can’t have cows milk myself but do have occasional goat or a cheeky piece of chocolate.

Any help appreciated!