Dog behaviour Sam who is a Jack Russell age 7 after a booster injection on has started chewing wood?

sounds like he is bored ... i don't think it has anything to do with the shots or pining, i think it is lack of exercise ... but why are you giving a 7 year old dog boosters ??? you don't have to muzzle him, you can use some two-sided tape and cover the area he is chewing with tin foil ... that is usually enough to keep them away ... you don't have to keep it there forever, just for a month or two so he gets the idea you don't like that ...