Hi,
I understand your agony. You suffer from heel spur. A sudden increase in weight can be a factor. Other factors may include tightening of calf muscles, flattening of the arch, walking abnormalities etc. Wear arch-supportive insoles. Limit activity, rest, and resume work. Avoid too much of walking or weight bearing. Use ice packs in the morning and heat packs in the evening on the affected area to reduce pain. Consult a physiotherapist who will teach you stretching exercise and continue them along with other options. Medicines such as NSAIDs provide only temporary relief. Consult a physician. Take care.