i had a depo injection almost two weeks ago into my upper buttock within minutes my back started to ache and after 2 hours i couldnt walk up the stairs properly every day for a week i had a lower to mid back ache but then it got so bad the following week i could barely walk sit or lie down.  my gp sent me for an xray but that came back normal so its not spinal.  I have not been able to work all week and i am keen to get back.  Could the nurse have accidently put the injection into the wrong area.  Ive been having these injections for 16 years and have never had any problems before.  I have had two massages by a clinical sports massuese but they have not relieved the pain either.
While this is clearly painful and dysfunctional, the anatomy is such that the nurse could not have done anything dangerous with the injection. She simply did it in a way that irritated the local muscles and sent them into spasm. So, topical ice, rest, and anti-inflammatory medications (Advil/allele) should do the trick. No need to worry.