Normally, puppies at shelters or rescues OR held back by their breeder (until more mature) are to GET shots starting at 7 weeks. There is no EARTHLY reason to wait until 11 or 12 weeks of age to start protecting the puppy from Parvo & Distemper.
If you started the shots at 11 weeks and got them (as the STANDARD dosing of a vaccine (booster HIGHLY suggested by most vets & breeders ) every TWO WEEKS, he should have gotten the next one at 13 weeks then gotten the last booster @ 15 weeks and rabies next @ 17 weeks.
Most vets tell you – your puppy can go to puppy classes 2 weeks after the second set and BEFORE the 3rd booster. [Of course we are not having many obedience classes at this point] but your vet’s instructions on YOUR “required” BEHAVIOR, as well as the poor choices (to NOT start vaccinations) by whomever you got the puppy from, have all been very ABNORMAL.]
Had you WAITED to get the puppy, until you had a safe PRIVATE yard; your Chi puppy could have started being housebroken (outside) as soon as it reached your home.
Now your puppy is not well socialized (to the outside, grass, sights, sounds, people, etc., etc.) and afraid or lacking confidence about going outside. Time, and many trips WITH you to the yard (play time in the yard) and many events that are positive (in that location) will help. That can include finding hidden caches of treats, or starting “nose work”, etc.
However, many dogs have NO INTEREST in being outside any LONGER than elimination takes, if YOU ARE NOT THERE, so expecting puppy to STAY outside is a JOKE. Dogs are companion animals & you have made this one MORE SO (if not super dependent on you) by preventing any outdoor excursions until 6 months of age. That’s “the hole” you choose (by your collective decisions)…. to put yourselves INTO.