Advice needed on latching please!

Today is my first time home with my baby boy. At the hospital he was latching fine after a few tries and easily feeding. Now my milk has come in and my breast are significantly larger feel very full. I'm having a hard time getting him to latch now. I've tried all the nipple holds I was taught but he doesn't seem to be opening his mouth wide enough. It's starting to get painful, he's frustrated and I don't want to end up engorged. Any tips or advice would help!