I have lower back pain on the right side of my body, slightly below my ribs. It started 3 hours ago. No fever. No headache. Pain is sever?

Possible kidney ston. Others include gallbladder stone disease. The kidney stone pain may radiate downward towards the groin and may show blood in urine (dark urine). Gallbladder pain may radiate upward towards shoulder blades. Since you mentioned "severe", you probably need to visit the emergency department for x ray or ultrasound, urinalysis, and pain control.
Back pain below the. The type of back pain you describe if it is associated with blood in urine and difficulty passing urine could be due to a stone in kidney or ureter.If there are no urinary symptoms and pain in back radiates to rt upper abdomen then it can be due to gall bladder problem with or without gall bladder stones.In ay case you need to see your md or go to er and get evaluated and cat scan and blood/urine.