Answers:
Please provide a more detailed history of the strain. Could be kidneys, musculoskeletal, or form of shingles (herpes sin herpetiform, niggle on skin short typical rash).
It could be a possible kidney infection. See your GP, they can oblige you better than anyone here. I enjoy have kidney infections and they are horrible.
You might enjoy bruised something. It will hurt for a few days. I would recommend that you put warmth on it. If it hurts for over a week, I would recommend that you stir to the doctors. I hope that this answers your cross-question, thankfulness, and, obedient luck,
~ Hound Lover!