What Causes Stomach Ache And Chest Pain In A Child?

I have a 10 yr. old son that over the past 9 mn. or so gets severe belly pain & sometimes chest pain. I have taken him to numerous yrgent cares & even E.R due to it happens more at night. They have done EKG`s, x-rays, some have given him anti heartburn meds. The last week in the morning when he eats he complains about stomach pain & says it lasts hours, sometimes he even brings home most of his lunch he didn`t eat, now the last two nights he is throwing up around bedtime with belly pain. He is throwing up now, I have given him anti naseau med. he just throws up. Ant suggestions. Could this be his gallbladder, I had mine out & it runs in family. Don t know wht to do. Going to Dr`s in morning.