I would see a pediatric allergist. It could be allergies and if he's having problems breathing, that can lead to bad sleeping, not being able to get into a deep sleep, bad dreams from oxygen deprivation, etc. I would also see the chiropractor. I LOVE mine and plan on taking my 2.5 year old to see him next week.
I wouldn't let him sleep with you though. If you start that, he's never going to stop wanting to come in with you. You could try one of the Fisher Price aquarium crib toys. It plays soft music with soft lights. Both of my boys still use it. I'll hear the music come on in the middle of the night but when I check, both kids are sound asleep. It helps them fall back asleep when its dark and they wake up scared.
Good Luck.