maybe you DO have water in your ear. I presume you have taken a bath or shower recently, at least I hope you have.(well, I'm sure your significant other hopes you have
the fact it causes pain makes me believe it is an infection. although it could be a wax build-up. I found a great ear wax remover. It;s made by Murine. It actually dissolves the wax and then you gently flush the canal with warm water (there are directions).
You could have water trapped behing wax even.
with the pain, you might consider a visit to the doc.