I have been experiencing upper right abdominal pain on a daily basis for 5 months, no solution from doctor?

I am a 28 year old female. I have been experiencing upper right abdominal pain on a daily basis for 5 months. I have normal bowel movements daily, no nausea, no fever, no vomiting, no other symptoms except this side pain. It ranges from a sharp, quick burning pain to a constant dull pain and happens several times throughout the day and doesn’t seem to be connected to food intake. I have had blood work done, an upper abdominal ultrasound, a breath test to see if it’s an ulcer — all came back clear. I was put on Nexium for 14 days, the pain went away on days 12,13, and 14 and I was pain free for about 5 days after and then the pains returned. My doctor wants to put me on daily Nexium without explaining what’s going on and I don’t want this to be a cover up to a real problem or a medicine I have to live on the rest of my life. If helpful, I have gained about 30 lbs over the last 8 months after switching to a desk job – this has made me about 15 lbs overweight. The only medication I take is a daily birth control pill: Lo Loestrin Fe. Any help or insight into this pain would be appreciated.