I can remember many nights when Elyse would get up almost every hour for no apparent reason. She would not settle herself either - just cry harder and harder. There was nothing that we knew of to do, but endure it. (Sorry) Some will sleep better in a swing, though. You could try that. She eventually outgrew it, but at three now, she still wakes up regularly at night, and needs to be tucked in and settled again. Our second daughter was never that way. We treated them both the same, but one could settle herself, and was easy going, the other couldn't. They have been that way since the minute they were born.
I can totally sympathize with your struggle. It is not a fun time, and you are no doubt exhausted! I hope it doesn't last too long. (By the way, have you tried chiropractic care for your son? It helped Elyse's general fussiness quite a bit. We took her at 6 weeks. She was still not an easy baby, but it really improved. )
All the best!