for the first few days he was doing it all on the mat and we was giving him praise and treats now i keep catching him going near buy the mat in all different places, we have bought the urine free carpet sampoos but as he has a little cough and cold and on medication from the vet he cant have his second jab to go outside, can anyone recomend anything we can do?
Okay, the first answer is ridiculous. Mat training is perfectly fine. It has a scent that attracts the dogs to “go” on it, sometimes they feel that going neerbye is just as good though. Correct this by scolding him when you see him, please dont be physical. btw, scolding after a little bit, not right away, is pointless as he had already forgotten, especially as a young puppy. Dont let him be there while you clean it as it gives him the wrong message. As a young puppy this is bound to happen so just give it time. The medication can also be the cause as it usually does give them weird behaviors and some side effects. Be stern as he may be testing you.
Hope that helped!!!!! 
yes I do have a recommendation; don’t “mat” train him, take him outside! This means getting up frequently in the middle of the night and after each meal and it is a huge amount of time and responsibility.
I hope you are using a crate as well.
Shih tzu are difficult to potty train as they are so cute but not that bright.
References :
potty trained my shih tzu and both of my mom’s
Okay, the first answer is ridiculous. Mat training is perfectly fine. It has a scent that attracts the dogs to “go” on it, sometimes they feel that going neerbye is just as good though. Correct this by scolding him when you see him, please dont be physical. btw, scolding after a little bit, not right away, is pointless as he had already forgotten, especially as a young puppy. Dont let him be there while you clean it as it gives him the wrong message. As a young puppy this is bound to happen so just give it time. The medication can also be the cause as it usually does give them weird behaviors and some side effects. Be stern as he may be testing you.
Hope that helped!!!!!
References :