3 week old seems uncomfortable

🙈🙉🙊 • Mom to 2 amazing little boys.
He sleeps great when he's on our chest during the day. Once it's time for bed and we lay him in his rock and play he gets really squirmy and is up every 45-60 minutes the rest of the night. I've tried gas drops. I just moved everything to the living room and I put him in his swing. That doesn't seem to help either. He's not awake and wanting to socialize. He's definitely tired but will only sleep in short bursts unless on his stomach one of us. We do not and will not cosleep. I took him in to get checked for reflux because his brother had it too. She said he was gaining plenty of weight and babies with reflux generally have weight gain issues so she wouldn't treat him. I can tell hes uncomfortable and I'm at a loss...and exhausted..