If he's got a stuffy nose it might be making it hard for him to breath and waking him up. This happened to my DS when he was young once. I got DH to hold him in the bathroom whilst I had a steaming hot shower to try and help clear his nose. That helped a bit, the steam.
I would also check his temperature, how many wet nappies has he had, how he is feeding (if he is turning his head a lot when feeding it could be oral thrush or an ear infection).

You might also find that he's just overtired, DS is a horror to settle when he's overtired. If he hasn't slept enough because of teething, or we've been out or a cold etc, he will get super overtired and be a nightmare (I lie down in bed with him and boob feed him to sleep in this situation, but not sure if you BF or not).