Podiatrist vs. Orthopedist: Who is best at treating foot pain?

The orthopedist should give a valid reason for his claim. If your podiatrist recommended plastic inserts, and they worked for you then I would trust the podiatrist. Maybe you can think of visiting another orthopedist to see if he tells the same thing. And a depo-medrol lidocaineinjection could have pain afterward, but if it doesn't stop then visit a doctor.

The recommendation of your orthopaedist to not use plastic orthotics could in fact be a fair one to make. It depends, however, on the type of condition you are currently struggling with. Usually, softer orthotics that relieve pressure areas in the foot, while lessening some of the shock as the foot strikes the ground. 

A second option may be helpful, if that is an option for you. It’ll be valuable in determining which direction you should go in regarding the type of orthotics you should use. Your podiatrist will aid you in diagnosing and treating conditions of the foot and lower leg, while the orthopedist can best provide you with the orthotics you need to reduce your symptoms.  

The reaction to the injection is relatively normal as the body has an initial inflammatory reaction to the injection into the joint itself. If the pain doesn’t subside, seek medical advice regarding this.