I suddenly developed heel pain in my right foot. very painfull somedays. what is causing this sudden pain?

Specific location?: Specific location matters a great deal. If the pain is at the bottom of the heel and hurts most with the initial steps of the morning, I would think plantar fasciitis. Heel spur would also be a consideration. Any lateral pain would make me think of a soft tissue injury (ligament or tendon). A physical exam and perhaps imaging may be in order.