How to deal with silent reflux during the night?

My LO wakes every 45 mins screaming arching back, thrashing. How can I help him at night? He has his medicines during the day. As soon as I pick him up he settles and sleeps or sometimes I have to do a comfort feed to help him drift off again. He just hates being laid flat for too long. I don’t know how I can get him to sleep any longer stretches in the cot. Please any advice would help! TIA