Hi thanks for your question. Noted you have pain only in right foot and acute presentation. Here you could have simple muscular strain at night during walking or any unaccoustemed activity that put pressure on foot by body weight. I want to suggest you for doing x ray foot both Ap and lateral view to just rule out small fracture if present. Foot supporting bandage can also be wear. Take rest. Take ibuprofen like analgesic and antiinflammatory drugs. Sometime ligament injury can also be present.If condition worsening then MRI can be done as further approach. So just now take rest and it will take some time for healing of muscle strain. Wish you good health. Take care. Dr.Parth goswami