If you are sure you are keeping a consistent daily routine and bedtime routine for your son, with the same
calming nightly routine (warm bath, singing, books, etc.) and bedtime hour, as well as a consistent nap schedule (even if he takes 5), and he is getting a total of 12 - 15 hours of actual undisturbed sleep, and you are still concerned with his irritability throughout the day and his need for swaddling, I would definitely seek a second medical opinion to rule out that anything medical or perhaps dietary is causing his fussiness.
But yeah, it's kind of just a
nightly routine where she knows that we're gonna have a bath, you're gonna get rubbed down in coconut oil, it's just a
calming thing where she knows it's night - night time.