does your baby do this?

Hi all. My almost 11 month old baby boy does this thing where it sounds like he's pushing and he's grunting but he's not pooping.. he sometimes does it while he's eating.. or if he's sitting somewhere.. sometimes my mom will say oh he's mad because it sounds like he is.. just wondering if any of your babies do something similar or the same?? Sometimes he'll just go ughhhhhhhh and seem mad but then he'll just act normal again.. he also has no teeth yet could that be bothering him??