Here's what to do, sit down with your feet relaxed, measure for fingers width up from your knee (towards your thigh) pinch the skin and inject in the middle of the pinched skin. (Alternate between your right and left thigh after each injection)
Note that the optimum place for the insulin absorption is the tummy (fastest absorption) so simply monitor your bg levels for the first days of trying your new injection site.
Hope you won't feel anymore discomfort.