Hi there!
Well, without an evaluation it would be difficult to point out cause. A few possibilities include fractures, dislocations, infections/ inflammations like tendonitis, arthritis, bursitis, fasciitis, growths like spurs etc. I would suggest an evaluation by an orthopedician for an appropriate diagnosis which may include a complete physical examination and a few tests such as imaging studies like X-rays/ MRI etc. After a cause is diagnosed, it can be managed accordingly. Meanwhile you may try some ice-packs and NSAIDS to help relieve the pain.
Hope this helps.
Take care!
I would def go to the doctor and have an x-ray done... if you continue to try and walk on it you could cause further damage... and if it happened at work, I would be sure to report it, so you can claim workers compensation before it's too late... good luck.