What is causing my diagnosed upper right side pain?

[HelpMyHealth1234]

I am a 28 year old female. slightly overweight (15 lbs). The only medication I am on is an oral contraceptive. For the past 5 months I have experienced a daily side pain in my upper right abdomen below my rib cage. No other symptoms - no nausea, fever, irregular bowel movement, loss of appetite- nothing. Just the side pain. It doesn't seem to be associated with what I eat. It occurs as either 1. a sharp burning pain several times in a row and multiple times throughout the day or 2. a constant dull lingering pain. Pain level is about a 3 and has never awaken me at night or caused me to stop in my tracks. It's strictly unpleasant and uncomfortable. I have had an upper quadrant ultrasound - normal with no gallstones, blood work - all normal and a breath test to see if it was an ulcer - negative. I was put on Nexium OTC for 14 days. The pain went away on days 12 and 13, came back on 14, but then was gone for about 5 days after the 14 day trial. Now it is back daily and my doctor said some people have to take Nexium daily but will not explain to me the underlying issue. I don't know if this is GERD or some type of inflammation, I don't want to just take Nexium long-term if it will only be covering up an issue and not truly treating it. Plus, I don't want to rely on a medication like this daily for many years and have read about the struggles of people taking this long-term. All this said, has anyone experience the same issues? What was your diagnosis and treatment?