In reply to Nathan Adam:
this is just by the way, no advice intended.
it was the 2nd time i'd had this thing with my foot when i'd got to see someone. the first time I just thought I'd wacked it or strained something.
guy was really good, asked a lot of questions to make sure it wasn't gout (phew!). and spent a lot of time essentially manipulating my big toe. that and a session of shock treatment (weird sensation but not unplesent). apparently it helps break down subsurface scar tissue.
I got the impression, unles I misunderstood, that my sesamoids had effectively dislocated and needed to be put back in their place. I was reccomended to do some pysical manipulation and stretching (pulling more like) of my toe. moving all the toe joints by hand would get a good knuckle-crack and the thing would feel a lot looser, that and pulling on the end of the toe to releave the compression within the joints.
seemed to work, at least it did for me.
ymmv. I'd still recomend you see another podiatrist, as a totally new no history consultation, and see what they say.