I told my dog to stay on my deck while I cut my grass one day, and now he will not leave the porch at all, no matter what I do. How do I get him to go and play in the yard like he used to.
My mother has a "middle of the pack" dog who is also very sensitive to any kind of reinforcement. Ex.stopped eating for a few meals because she yelled at him for sticking his face in her other dogs food dish, some dogs just associate reinforcement diffently... we call him emotional or sensitive. It can sometimes be hard to "speak dog" to let them know what you're specifically wanting them to do and not do.
The next few times you let your dog outside put a leash on him and go with him. You'll have to retrain him that the yard is "good". Lead him into the yard with a treat in hand and treat him the second he steps off the porch. Treat him when he goes off into the yard a little further, and release him off leash when you feel he's at a point where he's not trying to go back onto the porch. If he heads further into the yard, go to him (not call him towards you) and treat him again. Reinforce the behavior. If he turns around and goes back onto the porch put the leash back on him, stay calm and assertive but don't tell him no or bad dog.. So, that he doesn't think he cant be on the porch AT ALL (I'm assuming he has to walk on the porch to get back indoors). Treat him for coming onto the porch ONLY when you are ready for him to come back onto it. Good luck.