Hi again, Raian!
My Honey, who is a Golden Retriever, had that exact same problem in her first year of life. I worried and worried, but my vet explained the growing pains to me, and thankfully, eventually her limping stopped. I noticed that usually, it was worst when she was getting up after lying down for a while, or after a period of lots of exercise. I was just delighted it wasn't a hip problem.
When my second Golden, Lilly, started doing the same thing, I made the assumption that hers was the same problem. Hers didnt' go away though . At 1 1/2 years old, Lilly was diagnosed with mild hip dysplasia, but she is almost 3 now, and is doing terrific. We did some changes in her diet and have medication to help her when necessary, so she's doing great!
Logan