What Causes Nausea Along With Chest Pain And Excessive Phlegm?

Hi,

I had a Nissen Fundoplicatiom 3 weeks ago today. 3 days after surgery I went to A&E as liquids gave me chest pain. After a few days I got an appointment to see my surgeon who told me it was gas bloat. Now today I feel like there is a lot of phlegm dripping down and making me feel sick combined with the constant chest pain. The nueasua is too much and I can't stop the feeling of needing to throw up so my chest keeps heaving and only phlegm is coming up. It won't stop the pain or the neausa what can I do ?