Pain and hot/cold sensations in the feet are symptoms associated with diabetic neuropathy (nerve damage due to high blood sugar levels). This doesn't necessarily mean this is the cause of your difficulty, but it's a possible candidate given you have diabetes.
Neuropathy can develop quite quickly. Mine went from occasional and very mild pins and needles to very frequent and really quite painful in the space of about 12 months. Now that my BS is back within a normal range and under good control it's easing, slowly. Many others report similar improvements once BS control is improved.