I'm sorry to hear that you're experiencing knee and foot pain. Since you have already undergone some initial tests and started taking medications, the next step would be to get an X-ray of your knee and feet to determine the exact cause of your pain.
Based on your symptoms, it is possible that you could be suffering from arthritis or some form of joint inflammation.
Vitamin D and
calcium supplements may help to some extent, but it is important to identify the underlying cause of your pain for appropriate treatment.
I would recommend that you speak to your doctor again and ask if getting an X-ray would be appropriate at this stage. In the meantime, it may be helpful to avoid activities that aggravate your symptoms and to rest your knees and feet as much as possible.