When a monk came to say good bye to Chao-chou Tsung-shen (778-897), a brilliant Chinese Ch'an master.
-Where will you go?
The monk answered:
-Any place where I can learn Buddha dharma.
I don't think happiness and suffering can mix together. The absence of suffering is happiness and likewise the absence of happiness is suffering. You can be in pain yet you are still happy. Pain per se is not suffering. But you can suffer due to your pain. You can also suffer without pain.