It can take awhile to sync, leave it open for a little while maybe 30min, and see if it starts, I remember it took a little while for my wallet to start syncing.

I would not recommend trying to sell your coins directly from your pool, the software that most pools use(MPOS) is not able to withdraw less than the full confirmed balance; but if you have a deposit address for your account on an exchange you should be able to send your coins directly to the exchange.