shivering shih tzu

Question
i have a 5 week old shih tzu pup that is shivering, coughing a little and not that active anymore,for a day now. seem to be ok when i wrap him in a towel with the heater on him. what is the problem.

Answer
At this age those are signs of so many things that it is important you take the puppy to the vet immediately.  It could be very serious and contagious like distemper or parvo or it could be a genetic health issue related to low blood sugar, the heart, it could be a million things.  But, take the puppy and any of the remaining litter you have to the vet immediately.