My dog is a staffordshire terrior, he's rear legs are swollen and his tail has a little kink right at the top, he won't eat or drink, he won't walk no longer than 3 paces and he won't bark, wag his tail or move from where he lays unless you pick him up.
He is 16 months old, what could have caused this? What is wrong with him?

Please take him to a vet!

Was he hit by a car or did something fall on him?

I'm with WG here, suddenly not walking, refusing to move, swollen legs, he needs to see a vet. Just a guess but it sounds like an injury of some sort.
Please take him in.
Best Wishes
I hope you get him sorted out.

|Please get him to the vet as soon as you can! Unfortunately there is no way for us to tell what could be wrong. It could be anything from a bug bite to a blockage of some sort. Please have him checked out. Keep us posted.

Take care.