I had the same problem with my 6mon pit mix. The local pet store sold me something called a gental lead harness in stead of leading from the back it leads from the chest, I took a long time for my baby girl to get used to it (2-3 weeks) but it stop 95% of the pulling. I had to used that for about 4-6 weeks and now I can walk her with a regular harness and she prances along right at my side… It may not always work however if you go to a petco or something to that idea they have a 30 return so it won’t hurt to try.
Socialize him as much as possable but slowly… I have a female who is about 9 mons and we are now working with a group at our local PET CO which is geared towards getting them used to people. Sophie is now my 4th Pit and it seems that females tend to be more protective when they are younger and males as they get older but the sooner you socialize them the better and faster you will have results