Will I be drug tested?

Hello, I have pain in my feet from what I believe to be plantar fasciitis. I do door to door sales and the pain set in about month after I started working. So I was told I need to report this to my HR department. My question is will they drug test me? I know they normally drug test after a work place injury but can they drug test for something like plantar fasciitis since there is no possibility it could be drug related.