It seems to me that the actual process of stripping Harvey stresses him out so badly that he breaks out with bouts of intestinal distress - this is very common. The shaking is likely due to pain caused by his colitis, but it is difficult to say so with any certainty without actually seeing him in person. How long has the current bout been going on for? Is he eating and drinking ok? Any vomitting going on? These things are all important to know in order to assess his general health and hydration status. Any time a dog has any sort of diarrhea or pain, I worry about them being dehydrated and uncomfortable, so I would recommend taking Harvey to your vet - he may just need some different colitis medication, perhaps an antacid or an anti-gas medicine to ease his stomach. If he is very dehydrated, he will need to have fluid replacement therapy, but again, your vet will be able to assess this in person.
I would potentially recommend that when you take Harvey in to be stripped in future, you may like to ask your vet for a mild sedative so that he doesn't get so worked up! This may help to avoid future flare-ups of his intestinal problems.