Sleep training help!!!

Ok first off I'm posting this anonymously because I've learned a lot of mom's judge and this isn't a post for comments like "you shouldn't of become a mom" bs. This is about helping my baby, not me, I can go without sleep. So my son is about 7 months old. He's just recently switched into his crib about a month ago. Before then he was waking 4 to 6 times a night wanting to feed or be comforted. Now it's 3 to 4 times but when he's up.... he's up. If I do feed him, which I've tried to get down to 1 maybe 2 times a night, as soon as he's done he cries. If he wakes for his pacifier 15 mins later he's crying. I try rocking him in my arms which helps but the second I put him down he's wide awake screaming and crying again. He's not getting enough sleep leaving him cranky during the day which is why I need help. I don't think it's teething or at least there is no sign. No red, swollen gums. No low fever. No white spots. He's just always been a horrible sleeper. What should I do? I put him down semi awake so he goes to sleep on his own. Do I just let him cry it out whenever he wakes? Or what may help? Thanks in advance

Ps. He has a daily and nightly routine.