What can cause sharpish pain in the area described as the kidney which hurts mostly when you take a deep breath in- as if your organs are in a space to small for them (that's how it feels), can dehydration do this?

"Deep breaths" associated with sharp flank pain may be due to kidney injury b/c of "dehydration", but may also arise from pleural inflammation/irritation (the lining of the chest cavity and lung surface), denoting some temporary adhesion when the diaphragm is fully employed in the breath.

kidneys are situated in the flanks just below the rib cage. often back pain is wrongly ascribed to them. Pain with breath is more related to the diaphragm or the lungs or the ribcage muscles or ribs. So you have to be seen to determine the cause. Dehydration will not do this. Hope you feel better