I Started To Have Achy Back Pain Near My Waist

I started to have achy back pain near my waist on the right side this past Friday night. My temp was slightly elevated at 99.5 and I felt tired. On Saturday, the pain traveled around to the front of my abdomen on the right side. By Sunday my temp was back to normal. Stomach ache still persists, especially when I breathe deeply or try to lift. It's less when sitting still. I am still somewhat tired with no elevated temp. Any idea what might be causing this pain? I am a 41 year old female in good general health. Thank you.