Loud belching and grains out with it.

From seven months I have been suffering from loud belching and food particles coming out with it sometimes . and from an year I have also been suffering from insomnia . I feel so irritated and belching occurs almost 30-40 times a day and food coming out 4-5 times a day . it is similar to a small vomiting , I would say. My stomach always feels heavy and could not focus on things and couldn't sleep well. All the tests like ultrasound , endoscopy , TBC , rft , lft have been done and reports are normal What could be the possible reasons behind this ? What type of doctor , I should consult? Please suggest me a doctor ,where I could see myself From a month , I have taking activan 1 mg and mirtzapine 7.5 mg , one tablet a day and omenprazole and rabinprazole tablets , twice a day on prescription of a doctor. BT I do not see any improvement Please help me with this