Simba

My 9 year old jack Russell male is acting weird since almost two months now . To make a long story short , he has always been a candidate of occasional cramps . We changed his diet since a couple of years and the condition improved a lot .
Last October he had a very severe episode . We rushed to the vet . He examined him did x rays and blood works and the diagnosis was : neck arthritis that caused the arched back and belly spasms due to severe pain . I wasn't convinced as I knew he used to get those cramps when he was much younger .
I ran from vet to vet and always the same . Meanwhile he was eating a, urinating and pooping normally . One day he looked very very sick and by the end of the day he was shaking from pain and fever . We rushed to the vet that took our call as it was past midnight and we don't ve vet emergencies in our country . Upon examining him he said that he has very inflamed intestines and gave him antibiotic and cortison shots . We went home with a prescription to follow for 14 days . The next day our lovely dog was himself again . First time since a month .
3 weeks later another attack , not as severe but quiet bad . I gave him a cortison shot ( vet instructions on the phone ) . Visited the vet early morning . Again intestinal inflammation . Again antibiotics but only for four days . They ended yesterday . He is better but today he seems to be stressed again.
Will list down all tests done and all medications given till now . Before that I must note that during this period there was one night where he vomited 18 times .otherwise never again and he had never had diarrhea .
My very big concern is he doesn't touch his water bowl AT ALL .
He is on a bland diet .

Tests done
X ray
Ultrasound at 3 different vets
Blood works
In my country special pancreatitis test not available so only Amylase and Lypase were done
Urine and stool analysis
ANY CLUE

Why don't I get any answers ?

What are u feeding?

Bland diet . Chicken , carrots. Zucchini and potatoes