However Paul was quite clear in saying, "I rejoice in what I am suffering for you..." (Col 1:24). Paul found joy in his suffering for others and, moreover, he aspired to suffer for the Lord, "I want to know Christ---yes, to know the power of his resurrection and participation in his sufferings, becoming like him in his death" ((Phil 3:10).
So, were the ancient ascetics correct in seeking ways to deny, deprive and even cause pain to their bodies in order to achieve a higher state of holiness? Are we to seek out ways to inflict pain or injury upon ourselves so we can be spiritually enriched? Not!
The point Paul is making is that serving others often entails personal sacrifice, that following in the steps of Jesus will put the crosshairs of the Enemy on you, that seeking out and doing good for others can cause you to experience pain but is of personal value because "… suffering produces perseverance; perseverance, character; and character, hope..." (Rom 5:3-4).
The joy of suffering is not found by seeking out ways to inflict personal pain or injury bur in finding ways to personally serve the Lord or enrich another. The suffering or sacrifice found in giving oneself for another is cause for rejoicing instead of wailing because it is an indicator of the good you have done and it strengthens you against the attacks of the Enemy as you grow in perseverance and character.
God doesn't want us to seek martyrdom but rather not to run from opportunities to oppose the Enemy by doing good that may result in personal sacrifice or pain. Jus' Sayn.