I agree with the comments and suggestions made by JayBay. I would recommend you have both dogs checked by your veterinarian to rule out any illness or physical problems.
Then I recommend you contact a good trainer and let him/her teach you how to effectively communicate and train your dogs. Training a dog is not something we automatically or intuitively know how to do. It is very helpful to get expert assistance when you are having problems. Having an experienced trainer observe your interactions with your dogs and their responses to you will be very enlightening. It may not take many sessions for a trainer to help you immensely.
JayBay is right about exercise as well. Jack Russells are very, very energetic dogs and need a daily outlet for all that energy. They should be taken for a very long walk or a good run every day. It is true - a tired dog is a good dog. A bored dog without an outlet for its energy is going to get itself into trouble looking for some way to entertain itself.
I'm not a vet, but can you describe how you discipline your dogs? You may be inadvertently training them to do the very behavior you don't want. There is also a big difference between punishment and discipline. You want to be able to communicate rules, boundaries and limitations to your dogs using positive reinforcement rather than negative consequences. Simply put, that means rewarding the behavior you're asking for. Training can teach you how to communicate what you want to your dog along with when and how to reward that behavior.
As pet owners, we need to pet-proof our homes just as we would for our children. Ingested clothing can kill a dog if it obstructs the intestines. If clothing items are accessible to the dogs, how are they to know they aren't fair game for use as toys? Keep these items picked up and only allow access to appropriate dog toys.
Regarding Jackson, I think he needs a vet exam. It sounds like he has a physical medical problem based on the change of urination. He may have a urinary tract infection and simply can't hold it in. Add that to a pain response when you pick him up and it sounds like a physical issue there.
There's an old saying that I always stand by: A tired dog is a good dog. Daily exercise is so important for both physical and mental health. If a dog gets appropriate walking exercise daily, he will be far less likely to get into trouble. Their natural day is a cycle of exercise, food, nap and repeat. The closer you can create that schedule the better off you will all be. :-)