Gastric problems almost everyday.

Doctor, My grandmother had a bypass surgery in 2014 and since then she is following the deit recommended any the doctor. Now, She is facing gastric problems now mostly in the upper body. Most of the times she has gas in the chest area, due to this she faces heart jitter(dil ghabrana). And she says the the gas travels in the upper body. Some times in the head, due to which she has headaches almost everyday. And gas travels in the ear too due to which she is suffering from tinnitus now. She is also consuming medication for depression and Anxiety (Tab. Nexito 5). Her gastric problems are not cured and she is very sensitive to the medication, she faces these problems almost everyday I Kindly request you to please suggest something for her and what can we do her as a home remedy or any exercise. Thanks and Redards Filza Siddiqui (Granddaughter)