My dog eats a lot of socks, and I'm worried?

Well, my 2 and half year old black lab LOVES to eat socks. He dropped it for a long time and we thought he was okay but the last 2 months he has started doing it again, and it's very scary. We have tried different strategies, like yelling at him to scare him (we didn't have anything left to do), and sweetly coaxing him. He throws up socks a lot. Currently he has one in his stomach and he has been trying to throw it up for maybe 4 days. We can hear his stomach a lot and we think it's because of the sock. My mom says it's in his intestines or something... I love my animals and am scared for Mickie (my black lab). Does anyone have any suggestions? Also, we have taken him to the vet before they just say to wait for any progress.