Husband symptoms

I am going to book my husband a Dr appt, but he is having some symptoms that started around the same time recently

He’s having a pretty constant feeling in his lower stomach that moves. Mainly on his left side but he’s had it on the right side too. He says it doesn’t hurt exactly, just a pretty constant uncomfortable feeling

He’s also having mucus in his stool for the last month or so which he’s never had

The two symptoms started around the same time, like a month ago

Any idea what could be the cause of these?