My 3 week old chihuaha doesn't put any effort to walk... he's about to turn 4 weeks. All he does is waddle, but his hinds ben but he keeps his front legs locked straight. Does he have a disease or do I have to help, also how do I help him?

You need to take the puppy to the vet. What are you feeding him?

Is this a puppy you bought from someone or bred yourself?

Yes vet indeed. When did you get this puppy? It is way to young to be leaving it's mom and litter mates.