I guess I have a similar experience like this. I've tried to have conversations with bf but sometimes it just dies down cause he doesn't really respond much. I guess after a while I got used to the silence and it stopped bothering me. But it still bothers me a bit since he seems to have no trouble having conversations with his friends.

Maybe during the days you feel like you guys don't talk much but you want to, you guys can try doing an activity together so that you guys will be kinda forced to talk about it while doing it. Sometimes being comfortable around each other without having to talk is also okay. I hope you and your gf figure things out so that both of your needs are met. Good luck.