pulling on the leash

So we are at the 15 1/2 week mark and Toby has been quite the turd lately in many ways. I am assuming this is maybe an age related phase, but needing some advice on how to handle it, because I feel like what I'm doing must not be working well, as he keeps being a turd. He's getting better...

Hello, My 1 year old golden retriever is pulling on the leash like crazy, sometimes she is choking by that strong pulling. I don't know what to do.. I walk my dog 3-4 times a week (i don't have time it more often), but every day she is running and playing in my big backyard. :( Any Help? Thanks!