If you have recently (last two months or so...) introduced dairy or any other new foods, you may want to watch your son closely for additional symptoms. Night waking is an unusual, but common, symptom of food allergies in young children. My son appeared to be fine with everything he ate, including yogurt and cheese until he was about 13 months old. He stopped sleeping through the night, had a bloated belly and was constipated. It turns out he is allergicve to wheat, dairy and soy. He'll be three on August 3rd, and he is now able to eat yogurt, but no other dairy, and is still wheat-free. He is completely happy, healthy and SLEEPING again!
When he was having trouble with teething, I used to let him have a bottle with cold water in it. Even though he was never a real bottle-drinker, he would take it and the cold, along with the sucking, soothed him and he would go back to sleep. I hope this helps!