Conditions Wheeking in pain while pooping

I scheduled a vet appointment for my boar, Peanut, because for the past few days he has been wheeking while pooping (not peeing) his poops are tiny, they look like they come out broken. Sometimes it looks as though he struggles to pass his poop. My other boar who lives with Peanut is normal. They both eat the and diet, oxbow pellet, hay and green leaf lettuce & cilantro. I noticed Peanut started his soft painful wheeking a day after I cleaed out his, and my other boars anal sack. My other boar is good, but I am wondering if I somehow irritated him down there? I used olive oil as a lube. He had a few particles of stuff in his sack but nothing abnormal. This is the third time I have cleaned both of my boars anal sacks. Is it possible he could have stones? He turns 1 yr old mid November, so he's still a youngn. Any experience advice before I take him to the vet this evening would help! Thanks!