Hello , I've just gotten a golden retriver, his 11wks old. Buddy <--his name has taken all his reg shots but last 2 days , his been sneezing and having runny nose. Is this normal?

Could be allergies.. it's summer in the US now isn't is?
How often is he doing it?
Is he doing it after being outside or around a certain area or is it all the time?

Buddy is out at least 4 times a day, before we gotten him , he was in the pet shop and didn't have chance to be outside. Do you think
Us taking him outside and introducing him outdoor environment too quickly?

You said he had all his regular shots? Was this info from the pet shop or did your vet examine him and give him shots? At 11 weeks, I don't think he has had the full round of parvo vaccinations. If you haven't already done so, I cannot stress enough how important it is for a new owner to take his/her pet to his veterinarian for a thorough check up. If your vet has already seen him, call the office and report what is going on. It may simply be an allergy as Shaz suggests, or a cold. But, you won't know until you have a talk with his vet. It is better to be safe than sorry. Follow whatever advice the vet has to offer.