What Causes Pain In The Feet Soles While Standing?

Over the last few months the soles of my feet (generally around the heel and ball) have become very painful when I stand, particularly after being on your feet sometime and then sat down (to say watching an hour long TV programme) when I stand and the pain is excruciating. The pain subsides over the next few minutes (I need to stay on my feet) but it never goes away. Getting out of bed first thing can also be very painful. The pain generally feels like you are walking on a beach which is covered in large pebbles or sometimes it feels as if you have very large blisters on the soles of your feet (which I have not) and you are “sliding” on the fluid within the blister. When lying in bed the soles of my feet are very sensitive and sometimes feel cold.