Any suggestions for foot pain?

I usually wear flat shoes and a month ago I went to a business conference and wore shoes with a heel for three days and did a lot of walking. I am now having major foot pain in my right foot. The pain is on the bottom of the foot and wraps around the ball of my foot to the top of the heel. It even hurts when I am not puting weight on it. I go to bed at night and it rests for a couple of hours, but when I go to get out of bed I can hardly stand. (I have even fell when I tried to put weight on it suddenly in the middle of the night) There is no visible swelling or bruising, just intense pain. I have no health insurance, so I am alway's asking others advice and ideas. I wonder what it could be or at least what I can do to help the pain.

it sounds to me like plantar fasciitis, this is when you over stretch the ligament leading from the heel to the metatarsal heads.
it is a very common problem, but very painful, and sometimes chronic to get rid of.
actually a slight heel is good for it ( 1 inch) as it shortens the distance between the lagament attachment points, you can also buy arch supports from walgreeens, which go in u shoe and raise the arch a little.
you can also try ibuprofen gel rubbed into the area 4 times a day, and also anti inflammatory tablets, as it is essentially inflammation.
steroid shots work a treat if you can afford them.
you can also get someone to strap it for you - look up low dye strapping or figure of eight strapping - this can give you some real relief.
hope you get better soon