Woke up with severe back pain, rear leftt under ribs...nauseas also an hour ago I have had a bad stomach, mild nausea for two weeks. I am drinking water now...pain a bit better....my question...shall I go for tests to ER tomorrow.,,or rest and drink water. Should I assume this might be a kidneybstone? I did go into our ER perhaps four years ago with unknown severe pain ...tests were taken, nothing seen...told i might have passed a stone. Pain was gone by the time i left hospital.