desperate .. another sleep post

Hi Everyone, I'm truly desperate for more sleep suggestions for my 5 month old. I'm running on fumes here and don't know what I'm doing wrong. I remember my 18 mo old wasn't the best sleeper at this age, but she was great compared to this. My son is on a set schedule, wakes around 7:30 am, has 3 60-90 (ish) minute naps per day & is bathed and put to bed by 8 pm. He's such a happy baby, he's never tired or upset during the day & he's a great napper.  I'm being literal when I say he's up every 2 hours every night. One night it was even once an hour. He is NOT waking up to eat (I've tried feeding, he won't eat) doesn't need to be held or rocked to sleep, he just wakes up over and over half asleep just generally uncomfortable . My ped was shocked by his sleeping & suggested gripe water before bed to ease any discomfort but it hasn't helped. He won't fall asleep on his back, only his side or tummy so I'm not sure if I should invest in a sleep suit. Any suggestions would be greatly appreciated, I feel like I'm losing my mind 😓