Nausea and vomiting tendency. For this.

I have had this for the last 4 years or more than that, I get this nausea or vomiting kind of tendency it keeps on happening although I don't vomit but that feeling and the ook ook sound and it increases if I am doing some heavy work or if I am tensed due to something. I have got it checked by multiple doctors but every time they say that it's due to gas and suggest that I take pantoprazole everyday early in the morning. Which I have tried but does not help. Recently whenever I am eating a bit of rich or spicy food I get heart burn and pain on my upper abdomen, just between chest and abdomen and the pain is kind of severe and lasts for quite some hours. This used to happen earlier as well but maybe once in 6 months or so but now it has started to happen very often, maybe twice or thrice a week. Please suggest how and what may be the issue and what type of treatment I can get for this.