Severe pain in the right kidney area.

Hi doctor! This is Parveen Kumar. I work in night shift. I am having pain near my right kidney. It comes in waves and I am having the same issue from at least one year now, however, the pain is severe from last 3-5 days. It goes away when I lie down. I also have kidney stones (5-6mm max.) in both the kidneys. I had taken medicines for kidney stones. I drink beer every weekend. I thought it's a pain due to kidney stones but now I don't think that it's a pain cause of stones. May be it's a kidney infection, any UTI problem or something related to the kidney. It starts when I am in standing position for sometime. It is also there when I am seated, but not all the time. I don't have any other issues, but I have acidity problem because of night shift. Yesterday, I was at office and pain started. After few hours I felt stomach pain and loose motion started. Tomorrow, there is a plan to go on a tour with frnds. Pls suggest, can I leave for tour?? And what is the possible reason of pain? thnx.