Is IBS Need Endoscopy?

23 yo female with a history of IBS. A few months ago I began having significant stomach pain and nausea. I was treated for acid reflux with antacids and eventually sucralfate. I had a h. pylori test which came back negative as well as a barium swallow, which was not very clear but otherwise negative. The reflux was controlled but the stomach pain has continued. It is mostly located in the left upper quadrant and is sharp, pinching and also feels like a lot of pressure on my stomach. I am uninsured and cannot afford an upper endoscopy. Does this sound serious? What could cause my symptoms?