Am obese and now I have sharp pain in sole of my left feet. Is it because of weight. Please suggest few remedies to relieve the pain?

It's mechanical... Think of it this way. People with body types ranging from string beans to obese, and everything in between, can all have the same foot problems. To complicate things this same range of people may not ever have foot problems. Foot problems, like yours, seem to be a matter of foot function, or lack of it, more than any other factor. It is best to see a specialist for a proper evaluation and remedy.
Foot pain. Please start with a visit to your primary doctor. Let me know how things go.