Mandi, My totaly un-medical thought is that he is experiencing something related to the sugery he had. My wife had 3 C-sections (the boys) and she experienced all sorts of pains and strange sensations for a year or so after each. I have more pains in the neck that come and go and test my mental strength. I have asked my ENT if I have a problem and he has repetedly said NO that it is normal to have these sensations after the surgery.
Now I know your husband didn't have the same surgery but they were still in there cutting and undoubtedly there is some scar tissue and muscles that were not used while he was recovering and now he feels a bit better so they are getting a work out.
My GUT feeling is that you are going to have the best 4th of July vacation you have ever had
So plan on having your fun!