Hi, wow, I agree something just does not seem right. There are a few things that come to mind. I would suggest that you have your vet run a 4dx test which will test for several tick borne diseasse such as lyme disease, ehrlichiosis, anaplamosis, and heartworm disease. Jaw pain in dogs can be due to lyme disease or a disease called masticatory myositis. Also some Pitts can get a disease called babesiosis but that usually does not cause jaw pain. I would get your vet to first test for tick borne disease and to do a test to rule out masticatory myositis. Both of these are treated with antibiotics but the MM also is treated with steroids. This is where I would start. If this does not help,let me know if he develops any other symptoms. But, I agree, something is not right. Good luck and please let me know if I can assist you further. I will be happy to help in any way that I can. Cheers.