Cortisone shots

I have an elbow and knee injury from highschool football that is starting to bother me again and my doctor wants me to get cortisone shots in them. Isn't that a big no no?

I had two cortizone shots in left elbow 2011 and 2012. Now that I suspect I have lyme I wonder if that is why I got so sick the last couple of years. Another doc that needs to be confronted for his arrogance and narrow minded ness.