i can't walk and no doctor has helped

In the normal walking / gait process, I am unable to transfer weight to the front of my foot. Heel strike - fine, standing - fine, but when I go to finish the step, my entire foot just can't do it with that weight on the forefoot. I've had Xrays, MRIs, seen a podiatrist, an orthopedic surgeon, my regular doctor 3 times, tried everything I can think of - NSAIDs, RICE, 4 different pairs of shoes, even a walking boot for weeks - nothing helps.

I used to walk 4 miles a day every day and now I can't even limp around inside a grocery store. The only thing that any imagine test shows is a contusion of the calcaneus, but that isn't where any pain is, and even the podiatrist said he didn't think that was my problem.

If I try to walk - for even a short distance, I get whole-foot swelling everywhere - on top near the toes, all around the ankle, the whole thing starts to look like a water balloon. If I keep it elevated and stay off of it for a few days - it goes right back to normal and stays that way as long as I don't try to walk. No weakness in any tendon nor loss of range of motion with the ankle. I just cannot walk.

This has been going on for 9 months. The lack of exercise is causing massive systemic health issues that I didn't have before this all started. I am basically confined to a chair or bed.

Any ideas?