The difference between pain and suffering

Is there a difference? Is it just semantics?
I am attending a spiritual retreat this weekend and that came up in reference to grief. The answer was pain was to be embraced but suffering was to be let go. And that was supposed to make it better.
Honestly, I don't buy it.
I think telling someone in grief that they shouldn't be suffering and that suffering is a decision is placing an unnecessary guilt trip on the person who is already suffering. And make no mistake. Grief is hard, painful, and causes suffering.
The definition of suffering is to undergo or feel pain or distress. According to the person running the retreat suffering was a choice. An example of suffering would be to say that "this shouldn't be happening."  But it's OK to say that "this sucks".
For the life of me, I don't understand.
All I know is I am terribly sad. The sadness hurts. It is a physical feeling. I miss John with all my heart. I feel empty. Nothing matters.
Another remark made to me was "Would John want you to suffer?" Well, of course not. What kind of stupid question is that? But it happens. John and I have gone through things together that made us sad. We suffered together and knew it was a normal reaction to what we were going through. And we grew together in our sadness. We came through it. Together.
Now I don't have that.
There is nothing to get to on the other side. There is no "we" that can get me through this. There is only me. I know I will physically survive this. I know I can get things done. But I don't know how or if I can do anything for the hole that is in me. To do a play on words. I don't feel whole because of the hole.
It's not that I can't be whole. It's that I don't feel whole. I think there is a difference.
What all of this has taught me is that eventually no one wants to deal with this. When they say grief should last a year [another stupid notion], I think what they are saying is that no one can bear another's grief longer than that.
And that's OK. I think it's almost time for me to stop talking about this. To stop even writing about this. What else is there to say really?