Hi i have pain on the left side of my chest underneath by breast, been burping feel like vomiting hurts when i inhale and very uncomfortable at night?

Reflux: It sounds like you may have GERD, or gastroesophageal reflux. The symptoms of this are gassiness or bloating, nausea, sometimes pain, and it is usually worse when you lay down. You could try an anti acid medicine like zantac (ranitidine) or pepcid. If you don't improve, you develop worsening symptoms, or develop trouble breathing, call your doctor. Hope this helps!