puppy crying and jumping at playpen walls at night

first time pet parent here! i got a 7 week old pup about a week ago and things have been going okay, he pees and poops on his pee pads inside the play pen, loves to nap in his crate (always open) and is overall a fun little guy. the only issue is he screams and cries randomly in the middle of the night! his play pen is set up in my bedroom at the foot of my bed and he is there for most of the day except for when we play with him in other parts of the house. when it's time to sleep, he sleeps well and doesnt cry or jump at the pen walls when i shut the lights, and ive made it a routine to not talk to him or play w him after lights are shut so that he knows its sleep time, but at 2am everyday he has woken up and cried for about 30 minutes, where 10 minutes in i get up from my bed and tell him its okay and he stops but when i lie down he starts again. he eventually starts playin with chew toys and goes back to sleep but i just wanna know what you guys have done in these situations and when does it end? it's not about going potty since he always goes potty on the pee pads in the pen at night and its always available to him because his crate is open.