How do you know if you are under a trial or if you are just suffering? Hypothetically, if you are going through a painful situation:


Is it because God is trying to grow you/redirect you? 
Or is it a result of sinful actions?
In his book, Secrets of the Vine (based on John 15), Bruce Wilkinson addresses this very question.

In both situations, there is pain, so the presence of pain does not necessarily mean one is under God's discipline, although it could.

The key thing is to examine one's life to see if there is any unconfessed sin and to ask God  to reveal that.  One could also discuss it with a close friend or pastor to see if there is anything that other people have noticed.  If one is honest and there is nothing that God reveals, then it may be that the issue is purely one of growth.

Bruce Wilkinson distinguishes between the two by indicating that whenever there is pain because of sin, the pain continues until the person stops sinning.  However, if it is purely a matter of growth, the pain will continue until God has finished His work.