Really fussy

Anybody dealing with a very fussy 4 month old? The last week or so he has been fighting naps and just stays so grumpy all day. He sleeps great through the night. But during the day fights naps and just cries and cries and acts sooo tired and nothing makes him happy for more than a few minutes. I can't get anything done during the day because he doesn't wanna nap and just cries and cries