In Yogic science suffering is the result of ignorance. The human being is not in touch with reality. Reality is veiled by the senses, habitual patterns, energy blockages, belief systems that no longer work for the being. As a result human beings acting from a place of ignorance make mistakes thus creating karma and suffering happens.
More specifically in our times many yogis argue that the whole planet is undergoing massive changes by leaving Kali Yuga and entering Dwapara Yuga, a dark era to enter in a more enlightened area. This creates polarisations inside and outside of us. In the same way that the systems outside of us such as global and local economies, banks, society structures are being stressed, tested and transformed it is in the same way that this happens inside of us. We also need to leave behind the old, the heavy and the least useful and bring about more of our qualities. It is more important than ever for more of us to undergo trainings and prepare for these changes in the least painful way.
Another perspective helps us to rationalise suffering as the mechanism of life to help the human being make adjustments and align itself with a higher more accurate reality.