Has he been eating right i cant walk write when i dont eat and maybe he pulled something has he been doing a lot of activites he could just be sore there is a chance he could have arthrightis problems to
There isn't much information in what you wrote, so it's hard to get any idea really...but there could be lots of causes.
Has that happened suddenly? Or is it something that's been happening for a long time and kind of creeping up -only now it's suddenly worse?
Is he unwell in other ways -such as refusing to eat, drink, unable to pee and poop? Showing signs of pain? Or any other symptoms? Coughing....vomiting....diarrhea....anything else?
Dogs won't move or can't get up sometimes because of all sorts of different health reasons...some very serious indeed, and some which can easily be helped with pain relief, time and rest.
It's impossible or us to know if he's just pulled a muscle while playing....or is suffering from an internal bleed....or has severe arthritis or belly pain, or spinal injury, or a hundred other things.
The only real answer would be to get him checked out as soon as possible by a vet. I hope he will be okay.
It is nearly impossible to tell what the cause of the problem could be with the very scant amount of information given.
How old is your dog? Has it been acting perfectly normal until now or is this something you have noticed coming on for a while now?
What breed is your dog? Have you had it since it was a puppy or did you adopt it as an adult? How long has your dog been with you?
If you would please respond back and give us some more info we would be glad to offer any suggestions we can to work through this problem.