no, not a good idea ... ur muscles are wanting rest and hitting a bag isn't resting ... a nice jog will help, but working out isn't a good idea ... u should be alternating ur what body parts you workout so that you get about 3-4 days rest for one body part between each workout ...
ie.
mon - chest & triceps
wed - back & biceps
fri - shoulders and legs
... and u can run in-between ..
obviously you can change this around, depending on what areas you want to focus on