Is "pain" a noun or a verb?

For example, which of the following sentences is correct:

  1. My eyes are paining.
  2. There is a pain in my eyes.

Sentence 2 is correct: "there is a pain in my eyes".

Pain can be a noun or verb, for example:

The pain is terrible = noun

It pains me to see you this way = verb

For more details please see:

http://dictionary.reference.com/browse/pain