Hi mserica!
Sorry to hear you are having such discomfort!
I haven't heard of sharp pain associated with GERD. What you're describing actually sounds like it might be caused by gas. I've had severe sharp pains in my back & shoulder before, both caused by gas. Have you tried Beano or GasX? I suspect that may help alleviate your shoulder pain.
Your symptoms just began Wednesday? Are the alleviated by anything? Rolaids, Tums, Maalox? Do you notice if they get worse following certain foods? The burping does sound like a symptom of GERD, along with the indigestion. As for the bloating, I know I tend to get bloated after an uncomfortable episode.
Is there history of GERD in your family? Do you have a doctor you visit regularly? I'd say if you are still having these symptoms Monday, give him a call and see what he suggests.
I hope you feel better soon! Please keep us informed and let me know if you have any other questions/concerns! :)
Toni