I would also check for hotness to the touch, redness, fever common. what are your pain levels? I would make a call into your nurse on your insurance card and see what the recommendations are if it is an infection and hot to the touch I would say go to the ER because you don't want to chance losing your foot. But the burning sensation does sound like nerve pain. If the nerves for cut and they are regenerating you're going to feel that pain for a bit hopefully it will repair itself and it won't be an ongoing thing for you. Unfortunately, I had surgery 2 years ago and my nerves are still repairing them self! Best wishes keep us posted on how you're doing. I know about 10 years ago I had foot surgery and I thought it was the end of the world but after about 2 months it started to slowly get better you don't realize how much you use your foot until you can't use it.
Pain that feels like its on fire can be nerve damage. Anytime you have surgery nerves are cut which causes them to react with burning pain. I would check with your doctor. You wouldn't have redness or swelling with nerve pain. If you do have those symptoms you should see your dr so he can take a look and check and treat for infection.
Is you foot red and swollen and has the post operative wound healed? If not you have an infection so see your ER immediately.
Call your surgeon or whoever is on call for him and describe what's going on. Is the foot hot, warm, red, puffy/swollen?