Some good quotations I found:
"Pain is temporary, pride is forever" - Unknown
"Suffer the pain of discipline or suffer the pain of regret!" - Unknown
"I hated every minute of training, but I said, don't quit. Suffer now and live the rest of your life a champion." - Muhammad Ali, Boxer
"Fall down seven times, get up eight" -Chinese proverb
"The mind is the limit. As long as the mind can envision the fact that you can do something. You can do it, as long as you really believe 100 percent." -Arnold Schwarzenegger
Now get your ass up and go to the gym!