You can't help but want to cuddle the cute furball that is your puppy, but he might not return the affection in the same way. Not all puppies appreciate being held, and some can bite or squirm, desperate to get out of the situation. Several reasons for this dislike exist, but it doesn't mean he doesn't like you -- it's just the situation he's uncomfortable with.
You don't see dogs hugging each other in the wild. It's just not a natural behavior for them. When you pet a dog, it resembles another dog nuzzling him, but holding him can make him feel confined and insecure. Don't force your pup into your arms; this could make him develop a life-long resistance to being held. Instead, take your time and start slowly to get him used to greater amounts of confinement from your arms. For example, pet him on his head with your arm lying across his back. When he's comfortable with this, wrap one arm around him while petting him with the other hand. Gradually move toward picking him up again.
Your pup might not like being held because he hasn't been socialized properly. There's no way for you to know for sure how he was treated from birth until the time you got him. Puppies who were never held or who were treated roughly by people -- including by well-meaning children who picked them up in too harsh a manner -- might shy away from being held by you. Work to develop a loving relationship with your puppy before you try to pick him up, and introduce him slowly to a variety of new people and other animals to help him feel secure in his socialization. Giving him treats while you pet him can help encourage him to learn to appreciate your cuddles.
Fear of Heights
Imagine a puppy's-eye-view of the world, seeing everything from a few inches above the ground. Now think what it would be like to be swiftly lifted to several feet high. For a mature dog used to being held, this fast transition is normal, but to a puppy, it can be shocking and frightening. Add to this that many people turn puppies on their backs when holding them, and you add to the insecurity -- lying on their backs is a sign of submission or fear in many puppies. To teach your pup to love being held, start by sitting on the floor and holding him in your lap or arms and gradually work on holding him higher and securely, preferably with his feet supported by your arm or hands.
Puppies who typically don't mind being held but suddenly develop an aversion to it might be experiencing a medical problem that makes holding them uncomfortable. An ear infection could make it painful to be lifted quickly, for example, or he might have experienced a firm nip from another dog that left him bruised where you're picking him up. When you notice a sudden change in behavior, check with your vet to make sure there's no underlying medical problem.