srp says:

I have been having knee pain for a while. It was recently diagnosed as IT band syndrome, and I have begun physical therapy.

The PT noticed that the affected leg is slightly shorter than the other one, and suggested trying a heel pad in the affected leg to correct for the slight difference (he specifically said not to use a heel "cup" but to use a firmer pad)

Has anyone else done this? Recommendations on brands and where to buy them? I see several online vendors and several different types and brands.