Is my MacBook Pro hard drive dying?
Number one, backup immediately. At least if it dies you got all your data. I would recommend using a drive scanning utility to check your drive for hardware issues. S.M.A.R.T is useless, its pretty good that telling you that your drive is already dead. 

All the really good utils aren't free. Techtool Pro has been my tool of choice, however its not cheap. 

While you're at it install Disk Drill to get temps for your drive make sure its not over heating and also get some recovery mechanism in place (other than time machine). The basic edition is free. You can grab it from here: http://www.cleverfiles.com/