Had numerous abdomen x rays and CT scan also chest scan and x Ray and 2 ultra sound of liver and gallbladder could they have noticed a hiatal hernia?

Yes, on chest ct . Hiatal hernia should be able to be visualized on a chest ct unless it is very small . It usually wouldn't be visualized on liver/gallbladder ultrasounds. It might be visualized on x rays if it is large enough.