DS's nighttime sleep never was great, but it's even worse now these past few days!!

He's waking up with his eyes closed, but moaning/whining/crying. If I don't pick him up, he vomits everywhere from coughing so hard. When I do pick him up and hold him in a cradle position, he's arching is back and pushing away from me like he's in a very uncomfortable position. Switch arms - same thing. Upright seems to be the only position he likes, and even that takes him a couple minutes to settle down (he'll turn his head side to side and lean one way or the other, arch/push back a lil before relaxing and going back to sleep). What's going on with my lil man??? Any suggestions for a "cure"?