What Causes Chronic Pain In Abdomen?

Hello my name is Rena , My daughter Isabella has been hurting with pain of who knows what for we have treated with normal antacids.Still the has been consistant she crys .they did a ultra sound it said she had a giant air bubble.He wrote a script it did nt help . I feel so helpless as a mom I can t make it stop. She also had xrays and blood work ,nothing so what now? WHY DOES THESE SAY FREE WHEN THEY RE NOT I HAVE NO MONEY TO PAY I BARELY LIVE ON WHAT I MAKE WITH 8 PEOPLE ON 1,000 MONTH!