Biofreeze only has menthol and camphor in it. These stimulate the cold sensing nerves where it is applied. Biofreeze does not create cold...it simulates it.

Try putting it on the tops of the feet instead. The nerves go down
the tops of your feet to the toes.

What menthol and camphor do is block pain signals from heat sensing nerves. There are two types of fibers, heat sensing and cold sensing. What may have happened is you have a complex pain generator on your soles (maybe fasciitis), and when you blocked the heat feelings, the other pain became noticeable.

Most people feel a cooling sensation, hence the name of the product--BioFREEZE.

When the menthol wears off, the burning will return, but usually then it is at least a few hours.

Plantar fasciitis is a deeper in the tissues condition.
http://en.wikipedia.org/wiki/Plantar_fasciitis
You may or may not have a heel spur with this. I had this when I worked midnights, and the spur too, but it healed up and I have the spur still and no more symptoms of the fasciitis. Podiatrists like to operate on this, but the spurs will return. I suspect not all fasciitis is spur centered. But if you took Cipro or Levaquin or Avelox in the past, you could have tendon damage (some people completely detach their tendons) MONTHS after using those antibiotics. These drugs do something to the tendons causing them to degrade and detach from the bones and how this happens is still not understood.