in your case there can be elevated levels of uric acid or arthritis
or plantar fascitis or calcaneal spur
.. for this you have to see a good physician who can prescribe you some diagnostic tests and do the physical assessment of your feet and manage your ailment accordingly. as you have not mentioned about the nature of your pain for rest of the day, type of pain(i.e. sharp,dull,constant,intermittent),how it gets relieved(sitting or after rest) is also needed to be known. Also you havent written anything about your lifestyle(active or sedentary).But what you can do immediately is follow some of the pain relieving methods such as...
- do some ankle joint movements to and fro before leaving the bed in morning
- hot fomentation
- go to a physiotherapist for conservative treatment
but first go for a correct diagnosis..