Pretty much default behaviour for a gr'und!
My lurcher Ted is the same. He twisted his leg whilst running once, and twirled round and round screaming like a banshee, before collapsing in a whimpering heap in the grass. I was convinced he'd broken a leg and that I was going to have to carry 33Kg of pissed off dog two miles home. I manipulated his legs slowly to see which was hurt, got no reaction, offered him one of his training treats and he was up in a flash, and running around again. 🙄
Tweezers- see if you find the stinger if its still in.
Wasp stings are not barbed, so would not be left behind.
If the sting irritates Jim you can give him piriton. (standard disclaimer, etc)